<%BANNER%>
HIDE
 Copyright
 Title Page
 Board members/station staff
 Table of Contents
 Introduction
 Insects of the pecan
 Diseases of the pecan
 Insecticides and fungicides
 Warning on use and storage...
 Spray program for control of pecan...


FLAG IFAS PALMM UF



Insects and diseases of the pecan in Florida
CITATION SEARCH THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00028043/00001
 Material Information
Title: Insects and diseases of the pecan in Florida
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 74, 1 p. : ill. ; 23 cm.
Language: English
Creator: Phillips, Arthur M., 1903-
Cole, J. R ( John Rufus ), 1900-
Large, John R ( John Runyon ), 1901-
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1952
 Subjects
Subjects / Keywords: Pecan -- Diseases and pests -- Florida   ( lcsh )
Pecan -- Diseases and pests -- Control -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
General Note: Cover title.
General Note: "A revision of Bulletin 411."
General Note: "In cooperation with United States Department of Agiculture."
Funding: Florida Historical Agriculture and Rural Life
Statement of Responsibility: by Arthur M. Phillips, John R. Cole, and John R. Large.
 Record Information
Source Institution: Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location: Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida
Resource Identifier: oclc - 18267120
System ID: UF00028043:00001

Table of Contents
    Copyright
        Copyright
    Title Page
        Page 1
    Board members/station staff
        Page 2
        Page 3
    Table of Contents
        Page 4
    Introduction
        Page 5
    Insects of the pecan
        Page 5
        Pecan nut casebearer
            Page 6
            Page 7
            Page 8
        Pecan leaf casebearer
            Page 9
            Page 10
            Page 11
        Hickory shuckworm
            Page 12
            Page 13
            Page 14
        Southern green stinkbug
            Page 15
            Page 16
        Black pecan aphid
            Page 17
            Page 18
        Fall webworm
            Page 19
        Walnut caterpillar
            Page 19
            Page 20
            Page 21
        Twig girdler
            Page 22
            Page 23
        Pecan budmoth
            Page 24
        Pecan nursery casebearer
            Page 25
        Pecan phylloxera
            Page 25
            Page 26
        Pecan cigar casebearer
            Page 27
        May beetles
            Page 27
            Page 28
        Spittle bug
            Page 29
        Flatheaded apple tree borer
            Page 29
            Page 30
            Page 31
        Red-shouldered shot-hole borer
            Page 32
        Termites
            Page 32
            Page 33
        Pecan weevil
            Page 34
            Page 35
        Mites
            Page 36
            Page 37
        Pecan, catocala
            Page 38
    Diseases of the pecan
        Page 38
        Diseases due to specific organisms
            Page 39
            Scab
                Page 39
                Page 40
                Page 41
                Page 42
                Page 43
                Page 44
                Page 45
            Downy spot
                Page 46
            Pecan leaf blotch
                Page 47
            Brown leaf spot
                Page 48
            Gnomonia leaf spot
                Page 49
                Page 50
            Nursery blight
                Page 51
            Thread blight
                Page 52
            Powdery mildew
                Page 53
                Page 54
            Pink mold
                Page 55
            Wood rot
                Page 56
            Crown gall
                Page 57
                Page 58
        Diseases due to nutritional or environmental factors
            Page 59
            Rosette
                Page 59
                Page 60
                Page 61
                Page 62
                Page 63
                Page 64
            Little leaf
                Page 65
            Spanish moss
                Page 66
            Lichens
                Page 67
        Injuries due to climatic conditions
            Page 68
            Winter injury
                Page 68
            Sunscald
                Page 68
            Lightning injury
                Page 69
    Insecticides and fungicides
        Page 70
        Preparation of bordeaux mixture
            Page 70
        Ziram and Zineb
            Page 71
        DDT and parathion
            Page 72
        Summer oil emulsions
            Page 72
        Nicotine
            Page 72
        Lime-sulfur
            Page 72
        Combined sprays for insects and disease control
            Page 72
        Concentrate spraying
            Page 73
        The hydraulic spray outfit
            Page 73
        Applying the spray material
            Page 74
    Warning on use and storage of poisons
        Page 74
        Page 75
    Spray program for control of pecan insects and diseases
        Page 76
Full Text





HISTORIC NOTE


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.






Copyright 2005, Board of Trustees, University
of Florida







Bulletin 499


July 1952


(A Revision of Bulletin 411)


UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATIONS
WILLARD M. FIFIELD, Director
GAINESVILLE, FLORIDA
In Cooperation with United States Department of Agriculture





INSECTS AND DISEASES OF THE

PECAN IN FLORIDA


By ARTHUR M. PHILLIPS, JOHN R. COLE, and JOHN R. LARGE


w --.j


V-










BOARD OF CONTROL

Frank M. Harris, Chairman, St. Petersburg
Hollis Rinehart, Miami
Eli H. Fink, Jacksonville
George J. White, Sr., Mount Dora
Mrs. Alfred I. duPont, Jacksonville
George W. English, Jr., Ft. Lauderdale
W. Glenn Miller, Monticello
W. F. Powers, Secretary, Tallahassee

EXECUTIVE STAFF
J. Hillis Miller, Ph.D., President
J. Wayne Reitz, Ph.D., Provost for Agr.3
Willard M. Fifield, M.S., Director
J. R. Beckenbach, Ph.D., Asso. Director
L. O. Gratz, Ph.D., Assistant Director
Rogers L. Bartley, B.S., Admin. Mgir:
Geo. R. Freeman, B.S., Farm Superintendent


MAIN STATION, GAINESVILLE

AGRICULTURAL ECONOMICS
H. G. Hamilton, Ph.D., Agr. Economist'
R. E. L. Greene, Ph.D., Agr. Economic' a
M. A. Brooker, Ph D., Agr. Economist ?
Zach Savage, M.S.A., Associate
A. H. Spurlock, M.S.A., Associate
D. E. Alleger, M.S., Associate
D. L. Brooke, M.S.A., Assoc'ate4
M. R. Godwin, Ph.D., Associate
H. W. Little, M.S., Assistant
Tallmadge Bergen, B.S., Assistant
W. K. McPherson, M.S., Economist
Eric Thor, M.S., Asso. Agr. Economist
J. L. Tennant, Ph.ID., Agr. Economist

Orlando, Florida (Cooperative USDA)
G. Norman Rose, B.S., Asso. Agri. Economist
J. C. Townsend, Jr., B.S.A., Agricultural
Statistician 2
J. B. Owens, B.S.A., Agr. Statistician 2
J. K. Lankford, B.S., Agr. Statistician

AGRICULTURAL ENGINEERING
Frazier Rogers, M.S.A., ALn EI.I....-I '
J. M. Johnson, B.S.A.E., A.- EL.,:
J. M. Myers, B.S., Asso. ., r En..r. .-
J. S. Norton, M.S., Asst.:.\.: Eir.

AGRONOMY
Fred H. Hull, Ph.D., Agronomist 1
G. B. Killinger, Ph.D., Agronomist
H. C. Harris, Ph.D., Agronomist
R. W. Bledsoe, Ph.D., Agronom'st
W. A. Carver, Ph.D., Associa e
Darrel D. Morey, Ph.D., Associate 2
Fred A. Clark, M.S., Assistant
Myron C. Grennell, B.S.A.E., Assistant 4
E. S. Horner, Ph D., Assistant
A. T. Wallace, Ph.D., Assistant
D. E. McCloud, Ph.D., Assistant
H. E. Buckley, B.S.A., Ass'stant
E. C. Nutter, Ph.D., Asst. Agronomist

ANIMAL HUSBANDRY AND NUTRITION
T. J. Cunha, Ph.D., An. Husb.3 3
G. K. Davis, Ph.D., Animal Nutritiors' 3
S. John Folks, Jr., M.S., Asst. An. Husb.
Katherine Boney, B.S., Asst. Chem.
A. M. Pearson, Ph.D.. Asso. An. Husb 3
John P. Feaster, Ph.D., Asst. An. Natri.
H. D. Wallace, Ph.D., Asst. An. Husb.3
M. Koger, Ph.D., An. Husbandman 3
E. F. Johnston, M.S.. Asst. An. Husbandman
J. F. Hentges, Jr., Ph.D., Asst. An. Husb.

DAIRY SCIENCE
E. L. Fouts, Ph.D., Dairy Tech.1
R. B. Becker, Ph.D., Dairy Hush.8
S. P. Marshall, Ph.D., Asso. Dairy Hu-b.3
W. A. Krienke, M.S., Asso. Dairy Tech.3


P. T. Dix Arnold, M.S.A., Asst. Dairy Husb.2
Leon Mull, Ph.D., Asso. Dairy Tech.
H'. H. Wilkowske, Ph.D., Asst. Dairy Tech.
James M. Wing, M.S., Asst. Dairy Hush.

EDITORIAL
J. Francis Cooper, M.S.A., Editor
Clyde Beale, A.B J., Associa e Editor s
L. Odell Griffith, B.A.J., Asst. Editor
J. N. Joiner, B.S.A., Assistant Editor 3

ENTOMOLOGY
A. N. Tissot, Ph.D., Entomologis' L
L. C. Kuiterl, Ph.D., Associate
H. E. Bratley, M.S.A., Assistant
F. A. Bobinson, M.S., Asst. Apiculturist
R. E. Waites, Ph.D., Ass'. Entomologist

HOME ECONOMICS
Ouida D. Abbott, Ph.D., Home Econ.1
R. B. French, Ph.D., Biochemist

HORTICULTURE
G. H. Blackmon, M.S.A., Horticultur st 1
F. S. Jamison, Ph.D., Horticulturist 3
Albert P. Lorz, Ph.D., Horticulturist
R. K. Showalter, M.S., Asso. Hort.
R. A. Dennison, Ph.D., Asso. Hort.
R. H. Sharpe, M.S.. Asso. Horticulturist
V. F. Nettles, Ph D., Asso. Horticulturist
F. S. Lagasse, Ph.D., Asso. Hort.2
R. D. D'ckey, M.S.A., Asso. Hort.
L. H. Halsey, M.S.A., Asst. Hort.
C. B. Hall, Ph.D., Asst. Horticulturist
Austin Griffiths, Jr., B.S., Asst. Hort.
S. E. McF'adden, Jr., Ph D., Ass Hort.
C. H. VanMiddelem, Ph.D., Asst. Biochemist
Luford Thompson, M.S.A., Asst. Hort.

LIBRARY
Ida Keeling Cresap, Librarian

PLANT PATHOLOGY
W. B. Tisdale, Ph.D.. Plant Pathologist 3
Phares Decker, Ph.D., Plant Pathologist
Erdman West, M.S., Mycologist and Botanist
Bobert W. Earhart, Ph.D., Plant Path 2
Howard N. Miller, Ph.D., Asso. Plant Path.
Lillian E. Arnold, M.S., Asst. Botanist
C. W. Anderson, Ph.D., Asst. Plant Path.

POULTRY HUSBANDRY
N. R. Mehrhof, M.Agr., Poultry Hush.1 a
J. C. Driggers, Ph.D., Asso. Poultry Husb.

SOILS
F. B. Smith, Ph.D., Microbiologist'1
Gaylord M. Volk, Ph.D., Soils Chemist
J. R. Neller, Ph.D., Soils Chemist
Nathan Gammon, Jr., Ph D.. Soils Chemist
Ralph G. Leighty, B.S., Asst. S3il Surveyor
G. D. Thornton, Ph.D., Asso. Microbiologist
Charles F. Eno, Ph.D., Ass'. Soils Micro-
biologist 4
H. W. Winsor, B.S A., Assistant Chemist
R. E. Caldwell, S.A., Asst. Chemist
V. W. Carlisle, B.S., Asst. Soil Surveyor
J. H. Walker, M.S.A., Asst. Soil Surveyor
S. N. Edson, M. S., Asst. Soil Surveyor I
William K. Robertson, Ph.D., Asst. Chemist
O. E. Cruz, B.S.A., Asst. Soil Surveyor
W. G. Blue, Ph.D, Asst. Biochemist
J. G. A. Fiskel, Ph.D., Asst. Biochemist
H. F. Ross, B.S., Soils Microbiologist
L. C. Hammond, Ph.D., Asst. Soil Physicist
H. L. Breland, Ph.D., Asst. Soils Chem.

VETERINARY SCIENCE
D. A. Sanders, D.V.M., Veterinarian
M. W. Emmel, D'.V.M., Veterinarian s
C. F. Simpson, D.V.M., Asso. Veterinarian
L. E. Swanson, D.V.M., Parasi ologist
Glenn Van Ness, D.V.M., Asso. Pcu'try
Pathologist
W. R. Dennis, D.V.M., Asst. Paras:tologist










BRANCH STATIONS

NORTH FLORIDA STATION, QUINCY
W. C. Rhoades, Jr., M.S., Entomologist in
Charge
R. R. Kincaid, Ph.D., Plant Pathologist
L. G. Thompson, Jr., Ph.D., Soils Chemist
W. H. Chapman, M.S., Asso. Agronomist
Frank S. Baker, Jr., B.S., Asst. An. Husb.
T. E. Webb, B.S.A., Asst. Agronomist

Mobile Unit, Monticello
R. W. Wallace, B.S., Associate Agronomist

Mobile Unit, Marianna
R. W. Lipscomb, M.S., Associate Agronomist

Mobile Unit, Pensacola
R. L. Smith, M.S., Associate Agronomist

Mobile Unit, Chipley
J. B. White, B.S.A., Associate Agronomist

CITRUS STATION, LAKE ALFRED
A. F. Camp, Ph.D., Vice-Director in Charge
W. L. Tnompson, B.S., Entomologist
R. F. Suit, Ph.D., Plant Pathologist
E. P. Ducnarme, Ph.D., Asso. Plant Path.
C. R. Stearns, Jr., B.S.A., Asso. Chemist
J. W. Sites, Ph.D., Horticulturist
H. 0. Sterling, B.S., Asst. Horticulturist
H. J. Reitz, Ph.D., Horticulturist
Francine Fisher, M.S., Asst. Plant Path.
I. W. Wander, Ph.D., Soils Chemist
J. W. Kesterson, M.S., Asso. Chemist
R. Hendrickson, B.S., Asst. Chemist
Ivan Stewart, Ph.D., Asst. Biochemist
D. S. Prosser, Jr., B.S., Asst. Horticulturist
R. W. Olsen, B.S., Biochemist
F. W. Wenzel, Jr., Ph.D., Chemist
Alvin H. Rouse, M.S., Asso. Chemist
H. W. Ford, Ph.D., Asst. Horticulturist
L. C. Knorr, Ph.D., Asso. Histologist
R. M. Pratt, Ph.D., Asso. Ent.-Pathologist
J. W. Davis, B.S.A., Asst. in Ent.-Path.
W. A. Simanton, Ph.D., Entomologist
E. J. Deszyck, Ph.D., Asso. Horticulturist
C. D. Leonard, Ph.D., Asso. Horticulturist
W. T. Long, M.S., Asst. Horticulturist
M. H. Muma, Ph.D., Asso. Entomologist
F. J. Reynolds, Ph.D., Asso. Hort.
W. F. Spencer, Ph.D., Asst. Chem.
I. H. Holtsberg, B.S.A., Asst. Ento.-Path.
K. G. Townsend, B.S.A., Asst. Ento.-Path.
J. B. Weeks, B.S., Asst. Entomologist
R. B. Johnson, M.S., Asst. Entomologist
W. F. Newhall, Ph.D., Asst. Biochem.
W. I. Grierson-Jackson, Ph.D., Asst. Chem.

EVERGLADES STATION, BELLE GLADE
W. T. Forsee, Jr., Ph.D., Chemist Acting in
Charge
R. V. Allison, Ph.D., Fiber Technologist
Thomas Bregger, Ph.D., Physiologist
J. W. Randolph, M.S., Agricultural Engr.
R. W. Kidder, M.S., Asso. Animal Husb.
C. C. Seale, Associate Agronomist
N. C. Hayslip, B.S.A., Asso. Entomologist
E. A. Wolf, M.S., Asst. Horticulturist
W. H. Thames, M.S., Asst. Entomologist
W. N. Stoner, Ph.D., Asst. Plant Path.
W. A. Hills, M.S., Asso. Horticulturist
W. G. Genung, B.S.A., Asst. Entomologist
Frank V. Stevenson, M.S., Asso. Plant Path.
Robert J. Allen, Ph.D., Asst. Agronomist
V. E. Green, Ph.D., Asst. Agronomist
J. F. Darby, Ph.D., Asst. Plant Path.
H. L. Chapman, Jr., M.S.A., Asst. An. Hush.
Thos. G. Bowery, Ph.D., Asst. Entomologist
V. L. Guzman, Ph.D., Asst. Hort.
M. R. Bedsole, M.S.A., Asst. Chem.
J. C. Stephens, B.S., Drainage Engineer
A. E. Kretschmer, Jr., Ph.D., Asst. Soils
Chem.


SUB-TROPICAL STATION, HOMESTEAD
Geo. D. Ruehle, Ph.D., Vice-Dir. in Charge
D. O. Wolfenbarger, Ph.D., Entomologist
Francs B. Lincoln, Ph.D., Horticulturist
Robert A. Conover, Ph.D'., Plant Path.
John L. Malcolm, Ph.D., Asso. Soils Chemist
R. W. Harkness, Ph.D., Asst. Chemist
R. Bruce Ledin, Ph.D., Asst. Hor..
J. C. Noonan, M.S., Asst. Hort.
M. H. Gallatin, B.S., Soil Conservationist

WEST CENTRAL FLORIDA STATION,
BROOKSVILLE
William Jackson, B.S.A., Animal Husband-
man in Charge2

RANGE CATTLE STATION, ONA
W. G. Kirk, Ph.D., Vice-Director in Charge
E. M. Hodges, Ph.D., Agronomist
D. W. Jones, M.S., Asst. Soil Technologist

CENTRAL FLORIDA STATION, SANFORD
R. W. Ruprecht, Ph.D., Vice-Dir. in Charge
J. W. Wilson, Sc.D., Entomologist
P. J. Westgate, Ph.D., Asso. Hort.
Ben. F. Whitner, Jr., B.S.A., Asst. Hort.
Geo. Swank, Jr., Ph.D., Asst. Plant Path.

WEST FLORIDA STATION, JAY
C. E. Hutton, Ph.D., Vice-Director in Charge
I-. W. Lundy, B.S.A., Associate Agronomist
W. R. Langford, Ph.D., Asst. Agronomist

SUWANNEE VALLEY STATION,
LIVE OAK
G. E. Ritchey, M.S., Agronomist in Charge

GULF COAST STATION, BRADENTON
E. L. Spencer, Ph.D., Soils Chemist in Charge
E. G. Kelsheimer, Ph.D., Entomologist
David G. A. Kelbert, Asso. Horticulturist
Robert O. Magie, Ph.D., Plant Pathologist
J. M. Walter, Ph.D., Plant Pathologist
Donald S. Burgis, M.S.A., Asst. Hort.
C. M. Geraldson, Ph.D., Asst. Horticulturist
W. G. Cowperthwaite, Ph.D., Asst. Hort.
Amegda Jack, M.S., Asst. Soils Chemist


FIELD LABORATORIES

Watermelon, Grape, Pasture-Leesburg
C. C. Helms, Jr., B.S., Asst. Agronomist
L. H. Stover, Assistant in Horticulture
Strawberry-Plant City
A. N. Brooks, Ph.D., Plant Pathologist

Vegetables-Hastings
A. H. Eddins, Ph.D., Plant Path. in Charge
E. N. McCubbin, Ph.D., Horticulturist
T. M. Dobrovsky, Ph.D., Asst. Entomologist
Pecans-Monticello
A. M. Phillips, B.S., Asso. Entomologist 2
John R. Large, M.S., Asso. Plant Path.
Frost Forecasting-Lakeland
Warren O. Johnson, B.S., Meteorologist2


1 Head of Department
2 In cooperation with U. S.
3 Cooperative, other divisions, U. of F.
On leave









CONTENTS

PAGE
INSECTS OF THE PECAN ............. 5
Pecan Nut Casebearer ..-...-....... ... ..... ------.....- ..- 6
Pecan Leaf Casebearer ....................... ... ...-......... 9
Hickory Shuckworm ......... ..................... .........- 12
Southern Green Stinkbug ................. ---.... .........- ....-...... 15
Black Pecan Aphid .............. .............---.. ......... ... ... ........ 17
Fall Webworm ........... ............ ................. 19
Walnut Caterpillar ..........-............................................. 19
Twig Girdler ........ .......-.... ...............-- ........ ..... 22
Pecan Budmoth ........... ..-- --- ............. ...--. ... .. 24
Pecan Nursery Casebearer ...................... --.............. ......-- -- 25
Pecan Phylloxera ....................... .....- ..................... 25
Pecan Cigar Casebearer .................... ......................--- 27
May Beetles .................... ........ -......... ...... ..... --- 27
Spittle Bug ...-.. ........----.....-................ ..................... -. 29
Flatheaded Apple Tree Borer ............................ .............. 29
Red-Shouldered Shot-Hole Borer .............. .....................- ... 32
Termites ............ ............................................................... 32
Hickory Horned Devil ..... ...........-..... .. ...... -...... 32
Pecan Weevil ..................... ..... .. ................... ............. 34
M ites .... ......... ...... ...-. ... .......... ...... ........--................ 36
Pecan Catocala .............. ................. ............... ....... .......... 38
DISEASES OF THE PECAN -.......- ....-....... ... .........- ... .......-- .. 38
Diseases Due to Specific Organisms ............... -... .............----. 39
Scab ............................-..... ......-. .......- .. 39
Downy Spot .............. ................. ......................... 46
Pecan Leaf Blotch ........-...............................- ............. .. 47
Brown Leaf Spot ........ ............-............... ....- 48
Gnomonia Leaf Spot .....-......--.. ......- ................. ... ..... .. 49
Nursery Blight ..................... ...- ......... ............... .. 51
Thread Blight ..........................................-....... ........... 52
Powdery Mildew ................ ..--. .............................. ........ 53
Pink M old .................................... .. ................. ... 55
Wood Rot ............-...-............... ...-...-........... .. 56
Crown Gall ..................... ........................................ ......... 57
Diseases Due to Nutritional or Environmental Factors ..........-.... 59
Rosette ........................... .............................. ---... 59
Little Leaf ..... ...... .................................. 65
Spanish Moss --...... ........ .... ............... .....- ...... ....... ... 66
Lichens ....-- ...--. .- .................................... .. 67
Injuries Due to Climatic Conditions ................ ....... .............- -. 68
Winter Injury ..........................-.............................. ...... 68
Sunscald ... ........ ....... .-- .. .. .......- ....................... ........ 68
Lightning Injury ..........- ............................. ........... 69
INSECTICIDES AND FUNGICIDES ..............--.-...--............. .............. 70
Preparation of Bordeaux Mixture ................................... .......... 70
Ziram and Zineb .................................................... .. 71
DDT and Parathion ...................... ..................................... 72
Summer Oil Emulsions ................ .-........................... ........... 72
Nicotine ............ ----. .. ----........ ...................... ........ ...... .... 72
Lime-Sulfur ................-.......- ....- .............. .. ......... .72
Combined Sprays for Insects and Disease Control ................-...--. 72
Concentrate Spraying ............................-- ---.... ..... 73
The Hydraulic Spray Outfit ....................-.... ............ 73
Applying the Spray M material ----------. ...... ........ ........... ............ 74
WARNING ON USE AND STORAGE OF POISONS ......................-.--............... 74
SPRAY PROGRAM FOR CONTROL OF PECAN INSECTS AND DISEASES ............. 76










INSECTS AND DISEASES OF THE
PECAN IN FLORIDA

By ARTHUR M. PHILLIPS,1 JOHN R. COLE,2 and JOHN R. LARGE 3

INTRODUCTION

The planting and cultivation of pecans began extensively about
1900. Since that time insect pests and fungus diseases have
become of major importance, and are often a limiting factor in
the production of pecan nuts.
This bulletin is prepared for the pecan grower who has a large
enough acreage to justify the purchase of a spray machine suit-
able for spraying pecans. The control methods suggested in this
bulletin require the use of a spray machine having a pump ca-
pacity of 25 to 35 gallons per minute at 400 to 600 pounds pres-
sure.
In some areas close to cities the owner of a small orchard may
find commercial spray companies or a local farmer who will do
contract spraying. Several growers with small orchards might
cooperate and purchase a spray machine.
For the home or small orchard where spraying would be very
difficult, Blackmon and Sharpe 4 suggest top-working the trees
to varieties that are notably scab-resistant over wide areas.
Curtis and Stuart would be of first choice, with Elliott and Desir-
able among the newer varieties which appear to have promise.
For detailed information on top-working pecan trees, see Bulle-
tin 437.

INSECTS OF THE PECAN
Major changes have occurred in the importance of pecan in-
sect pests and in control measures used to combat them since
1945, when Bulletin 411 on Insects and Diseases of the Pecan
in Florida was published. The nut casebearer and shuckworm

SAssoc. Ento., Fruit Insect lnves., USDA Bur. Ento. & P1. Quar., and
Fla. Agri. Expt. Sta., Pecan Inves. Lab., Monticello, Fla.
2 Pathologist, Division of Fruit and Nut Crops and Diseases, Bureau of
Plant Industry, Soils and Agricultural Engineering, Agricultural Research
Administration, USDA, Albany, Georgia.
Associate Pathologist, Pecan Investigations Laboratory, Monticello.
Blackmon, G. H., and R. H. Sharpe. Pecan Growing in Florida, Fla.
Agr. Expt. Sta. Bul. 437, 1951.










INSECTS AND DISEASES OF THE
PECAN IN FLORIDA

By ARTHUR M. PHILLIPS,1 JOHN R. COLE,2 and JOHN R. LARGE 3

INTRODUCTION

The planting and cultivation of pecans began extensively about
1900. Since that time insect pests and fungus diseases have
become of major importance, and are often a limiting factor in
the production of pecan nuts.
This bulletin is prepared for the pecan grower who has a large
enough acreage to justify the purchase of a spray machine suit-
able for spraying pecans. The control methods suggested in this
bulletin require the use of a spray machine having a pump ca-
pacity of 25 to 35 gallons per minute at 400 to 600 pounds pres-
sure.
In some areas close to cities the owner of a small orchard may
find commercial spray companies or a local farmer who will do
contract spraying. Several growers with small orchards might
cooperate and purchase a spray machine.
For the home or small orchard where spraying would be very
difficult, Blackmon and Sharpe 4 suggest top-working the trees
to varieties that are notably scab-resistant over wide areas.
Curtis and Stuart would be of first choice, with Elliott and Desir-
able among the newer varieties which appear to have promise.
For detailed information on top-working pecan trees, see Bulle-
tin 437.

INSECTS OF THE PECAN
Major changes have occurred in the importance of pecan in-
sect pests and in control measures used to combat them since
1945, when Bulletin 411 on Insects and Diseases of the Pecan
in Florida was published. The nut casebearer and shuckworm

SAssoc. Ento., Fruit Insect lnves., USDA Bur. Ento. & P1. Quar., and
Fla. Agri. Expt. Sta., Pecan Inves. Lab., Monticello, Fla.
2 Pathologist, Division of Fruit and Nut Crops and Diseases, Bureau of
Plant Industry, Soils and Agricultural Engineering, Agricultural Research
Administration, USDA, Albany, Georgia.
Associate Pathologist, Pecan Investigations Laboratory, Monticello.
Blackmon, G. H., and R. H. Sharpe. Pecan Growing in Florida, Fla.
Agr. Expt. Sta. Bul. 437, 1951.







Florida Agricultural Experiment Stations


are still important pests, as they were then. In 1945 the pecan
leaf casebearer was one of the more important pests, at present
it is of comparatively little importance. The pecan weevil and
mites on pecans were unknown in Florida in 1945, but they are
among our more important pests now.;

PECAN NUT CASEBEARER
The pecan nut casebearer, Acrobasis caryae Grote, is one of
the most serious insect pests attacking the pecan in Florida. Its
damage is especially serious during seasons when trees set a light
crop or on varieties which generally are not heavy producers.
This insect passes the winter as a partly grown larva in an
inconspicuous small case, or hibernaculum, which is generally
found at the base of the bud where it joins the stem. The larvae
become active in the spring about the time the buds begin to
open. After feeding on the buds for a short time the larvae bore
into the young tender shoots, where they feed until full grown,
and then transform into the pupal stage mostly within the tun-
nelled shoots.
In Florida the adults, or moths, emerge from the latter part
of April to May 20. The appearance of the maximum number
of moths of this generation usually coincides fairly well with
the setting of the nuts. The moth is small (measuring only
about /8 inch across the expanded wings) and of a rather in-
conspicuous dark-gray color, with a ridge or tuft of long, dark
scales extending across the fore wing near the middle. The
moths lay their tiny, greenish-white eggs singly on the blossom
end of the nut, and usually at or near the base of the calyx lobes.
A single egg is usually laid in a cluster of nuts, although occa-
sionally two eggs may be present.
Most of the damage by this insect is caused by the larvae of
the first generation, which appear in May and early June. Soon
after hatching the young larvae usually descend and feed for a
short period on the buds just below the cluster of nuts and then
crawl back up and attack the newly set nuts, usually entering
them near the stem end. Infested nuts are easily recognized
by the characteristic masses of borings cast out by the larvae.

SAlthough statements on pecan insects in this bulletin are based to a
considerable extent on the work and experience of the first author, available
information elsewhere, especially USDA Farmers' Bulletin No. 1829, has
been drawn on freely, for which acknowledgment is here made. Acknowl-
edgment is also made for USDA photographs. This bulletin supersedes
Florida Experiment Station Bulletin 411.





Insects and Diseases of the Pecan in Florida


They are held together by fine silken threads (Fig. 1). A single
larva of this generation may destroy several nuts or an entire
cluster. The larvae mature and pupate in the nuts and the
moths of the second generation appear from the middle of June
to the first of July. As a rule the larvae of the second genera-
tion cause much less damage than those of the first, because
at that time the nuts are larger and only one or two are neces-
sary for the development of an individual larva (Fig. 2). Larvae
of later generations cause very little damage, as the nuts are
approaching maturity and the larvae feed on the outer part of
the shucks and on the foliage instead of in the nuts themselves.





Vt,




i/y



Fig. 1.-Young nuts showing injury by larvae of the pecan nut casebearer.
Usually there are only three generations of this insect a year,
although sometimes there is a partial fourth generation in Flor-
ida. Larvae of the third generation that do not complete their
life cycle the first year and larvae of the fourth generation (if
there is one) form the hibernacula or cases about the buds.
Contrary to the belief formerly held, it has been proved that
the pecan nut is not essential for the development of the pecan







Florida Agricultural Experiment Stations


nut casebearer.6 The larvae can feed and develop entirely on
foliage. This explains to some extent why this insect survives
in orchards when there are no nuts on the trees.


F_
















Fig. 2.-Cluster of nuts infested by the pecan nut casebearer.

Control.-Since larvae of the first generation cause the most
damage, spraying when the nuts are small, or shortly after first
generation eggs begin to hatch, is the most effective method of
controlling the pecan nut casebearer. The period for spraying
varies with the season, locality and variety of pecans. As a gen-
eral rule, the application of spray should be made when the tips
of the small nuts begin to turn brown. In Florida this is usually
between May 1 and 20. Use either 2 pounds of 50 percent DDT
wettable powder in 100 gallons water or 2 pounds 15 percent
parathion wettable powder in 100 gallons water. If a leaf scorch
condition caused by mites appears on DDT-sprayed trees, apply
a miticide as recommended for control of mites.
DDT and parathion may be used in combination with either a
6-2-100 bordeaux mixture or 2 pounds ziram (76 ) as recom-
mended in fungicide spray schedule for control of scab or foliage
diseases.
Note.-DDT and parathion are poisons and should be used only
Hill, S. 0., Pecan foliage as food for the pecan nut casebearer. Fla.
Ent. 23: 2: 27-29. 1940.







Insects and Diseases of the Pecan in Florida


as recommended by man-
ufacturers. See warn-
ing relative to handling -
these materials in back
of bulletin.
PECAN LEAF
CASEBEARER
The pecan leaf case-
bearer, Acrobasis juglan- .-
dis (LeB.), is also con-
sidered a serious pest of
the pecan in Florida. It
does its greatest damage
in early spring after the
larvae emerge from their
overwintering c a s e s,
when they feed on the
unfolding buds and
leaves (Fig. 3). In se-
vere infestations pecan c.:
trees may be kept in a
defoliated condition for
three or four weeks 4
(Fig. 4). This injury P
often causes a reduction
in the nut crop, and trees J .*.-
deprived of their foliage
in this manner may be
materially weakened.
These insects pass the
winter as larvae in small 7
cases or hibernacula
about the buds, similar
to those constructed by
the pecan nut casebearer.
After completing their -
development they trans- Fig. 3.-Injury to young buds in spring
form to pupae within caused by larvae of the pecan leaf case-
bearer.
their cases. The moths
usually appear from about the middle of May until the first of
August. The moth measures only about 2 inch across the ex-
panded wings, and the general color is grayish brown. The







Florida Agricultural Experiment Stations


adults are usually found hiding in debris at the base of the trees
or in the thick foliage. There is only one generation a year.


Fig. 4.-Pecan tree defoliated by larvae of the pecan leaf casebearer
in early spring.

The moths deposit their eggs on the under sides of the leave:
along a vein or near the junction of a vein with the midrib. The
young larvae may be found in their summer feeding cases (Fig.
5) on the under sides of the leaves from the middle of May until
November. The larvae feed very sparingly during the summer,
and rarely attain a length more than 1/16 inch by fall. During
the latter part of August or in early September the partly grown







Insects and Diseases of the Pecan in Florida


larvae start migrating from their summer feeding cases on the
leaves and form their overwintering cases around the buds.
Observations indicate that there is a very close connection be-
tween the falling of
the leaves and the
migration of the leaf
casebearer larvae, so
the migration period 's
varies, depending on
the variety of pe-
cans and the season.
Control.-DDT and
parathion, when ap-
plied for control of
the nut casebearer,
will also control the
leaf casebearer. If it
is not necessary to .
spray for control of
the nut casebearer,
the leaf casebearer
can be controlled by
spraying the trees in
late June or early
July with either 2 -
pounds of DDT 50 .
percent wettable
powder or 2 pounds '.' ~. "
of parathion 15 per- r
cent wettable powder
in 100 gallons water. "
On pecan varieties .:
that have scab, the
insecticides may be
combined with the .
fungicide in the third '" ;
or fourth application
of the spray schedule Fig. 5.-Feeding cases of young leaf casebearer
larvae (enlarged).
(Page 76). Only one
application is necessary, if the under sides of the leaves are well
covered.







Florida Agricultural Experiment Stations


HICKORY SHUCKWORM
The hickory shuckworm, Laspeyresia caryana (Fitch), also
commonly called the pecan shuckworm, is one of the most gen-
erally prevalent in-
S-- 1 sect pests of the pe-
Scan. It is primarily
I a nut-infesting pest.
The worms, or lar-
vae, destroy a few of
the developing nuts
during June, but
cause most damage
during July and Au-
gust, when the insect
iis capable of destroy-
Sing 50 percent or
more of the pecan
crop in seasons when
there is a light set of
nuts. Nuts punc-
Fig. 6.-Larvae of the hickory shuckworm in turned during mid-
immature pecan nut (enlarged). summer drop from
the trees and the lar-
vae complete their development in the interior of the immature
nuts (Fig. 6). During September and late fall, after the nut
shells have hardened, the larvae mine or tunnel the shucks (Fig.
7), which may prevent proper development of the kernels and
delay maturity. At harvest, heavily infested nuts have tight
shucks and the shells are stained with black marks.
This insect also feeds upon the various species of hickory and
the injury is similar, but often much more severe. The larvae
are often found also feeding in phylloxera galls on pecans in
early spring.
There are sometimes as many as four or five generations of
the shuckworm in a year in Florida. Moths of the spring brood,
or those that develop from the larvae that spend the winter in
pecan and hickory shucks, may emerge as early as the middle
of February. Peak emergence is usually during the latter part
of March and April. Most of these die before the pecan nuts
have set. However, moths of this brood may continue to emerge
from the old shucks throughout the entire summer. Peak emer-







Insects and Diseases of the Pecan in Florida


gence of this brood seems to
early species of hickory nuts.


coincide with the development of


Fig. 7.-Larvae of the hickory shuckworm in shuck of
pecan nut (enlarged).


The moths are very inconspicuous and are rarely noticed in
the orchard. Eggs are deposited on the young nuts or leaves.
Upon hatching, the tiny larvae gnaw their way into the green
nuts. Until the shell hardens, the larvae work in the interior
of the immature nuts and cause them to drop. Larvae of the
last generation attack only the shucks after the shells have
hardened and the nuts are approaching maturity. Full-grown
larvae pass the winter in shucks on the ground or in the trees.
Control.-Insecticides have not proved very satisfactory in
the control of the hickory shuckworm. A high percentage of
the larvae that winter in old pecan shucks may be killed by
gathering and destroying the shucks at harvest. However, this
is feasible only when the nuts are harvested on sheets. Plowing
the shucks under about March 1, after the larvae have pupated,
also will help to reduce the infestation of shuckworm during the
summer.
Partial control (about 50 percent) of the shuckworm is pos-


nearly mature







Florida Agricultural Experiment Stations


sible by keeping the infested drops covered with soil during July
and August when cultural practices permit. Deterioration of
the drops in the soil prevents the immature larvae from de-
veloping.7 This can best be accomplished by cultivating twice
with a disk tiller, sometimes called tiller plow or Wheatland
plow (Fig. 8). The ordinary disk harrow does not give effective
control because the soil is stirred without covering the drops
uniformly. The first turning under of drops with a disk tiller
should be made about July 15 and the second during the first
week in August, or after approximately a three-week interval.


Fig. 8.-Disk tiller in operation for control of hickory shuckworm.

The second turning should begin at exactly the same place where
the first commenced. Where infested drops are buried for three
weeks and then uncovered, no more moths emerge than where
the drops remain covered. The interval between the first and
second operations, however, should not be much longer than
three weeks, or moths will emerge from nuts that dropped since
the first cultivation. To cover with one tiller as much of the
orchard as possible within the limited time permitted for control,

7 From unpublished data of G. F. Moznette, USDA, Bureau of Ento-
mology and Plant Quarantine, Albany, Georgia.







Insects and Diseases of the Pecan in Florida


cultivation should be restricted at first to the area from the
trunks of the trees to the edge of the branches.
Where the orchard has received little or no cultivation in for-
mer years, the disk tiller should be set to plow three inches deep
the first season to avoid severe root damage. The second season
it can be set at four inches, which depth will be more effective
in covering the drops. In no case should the tiller be set deeper
than four inches, as too many feeder roots may be destroyed.
If a grower has only a few trees he should pick up the drops
during midsummer and remove them from the orchard and de-
stroy them.
SOUTHERN GREEN STINKBUG
The Southern green stinkbug, Nezara viridula (L.), or "pump-
kin bug," and certain other plant-feeding bugs have frequently
caused serious damage to the pecan crops of individual growers
in Florida. The feeding of these sucking insects produces the
trouble known to the pecan grower as "black pit" and causes
the nuts to drop prematurely if injured before the shells have
become hard. However, a similar condition is caused by the
hickory shuckworm. During the midsummer drop it may be
difficult for the grower to tell whether the drop was caused by
the work of the shuckworm or the sucking bugs.
After the nuts have passed the water stage and the shells
have become hard the puncture or injury by the stinkbug pro-
duces a condition known as kernel spot (Fig. 9) instead of black
pit. The spots on the kernel are decidedly bitter and this injury"
cannot be detected until the kernel has been removed from the
shell.
The adult stinkbug is shield-shaped (Fig. 10). It passes the
winter in the adult stage and is often active during periods of
mild weather. The eggs may be found in clusters on the under
sides of leaves of host plants from April to November. This bug
begins feeding on the nuts about the time they reach the water
stage and continues until the nuts are practically mature. There
may be as many as four generations in a year.
The Southern green stinkbug attacks a large number of plants,
both wild and cultivated, which serve as food for the young or
"nymphs" until they reach the adult stage. Pecan nuts are at-
tacked only by the adult bugs, which fly to the trees from plants
on which they feed as nymphs.
Control.-Due to the feeding habits of the Southern green
stinkbug, it is difficult to control this insect on pecans with insec-








Florida Agricultural Experiment Stations


ticides. Observations have indicated that when control measures
are necessary 2 pounds of parathion 15 percent wettable powder
will give effective control. The parathion may be used alone or
in combination with the fungicide applied for control of scab.
The black pit and kernel spot of pecans caused by the green
stinkbug and other plant bugs can be largely prevented by de-


i
71


Fig. 9.-Kernel spots on Schley pecan kernels. The upper and central
views show the location on the ridges and edges of the kernels. The lower
sections of kernels, cut through the spots, show the depth and extent of the
injury.


A 0.0
*^ *


cov-'







Insects and Diseases of the Pecan in Florida


stroying their host plants in and near pecan orchards. Where
the stinkbugs are a serious problem, such crops as cowpeas, soy-
beans, beans, squash, tomatoes and Crotalaria mucronata Desv.
(formerly C. striata DC.), should not be planted in or near the
orchard, and the orchard should be disked two or three times
during the summer to destroy native food plants.
BLACK PECAN APHID
Some seasons the black pecan aphid, Melanocallis caryaefoliae


4..

'I


. *.


Fig. 10.-Southern green stinkbug feeding on pecan nuts.








Florida Agricultural Experiment Stations


(Davis), causes considerable premature defoliation of pecan
trees. This aphid usually is more prevalent on trees that have
received a number of applications of bordeaux mixture but un-
sprayed trees may become heavily infested. The injury it causes
usually is most noticeable during August and September. First
signs of its presence are bright yellow spots, more or less rec-
tangular in shape, which appear on the leaflets around the punc-
tures where the aphids feed. These turn brown (Fig. 11) and
may cause the leaflet
r to drop prematurely.
Heavy premature de-
foliation has a direct
effect on the quality
of the current pecan
crop and on produc-
tion the following
year.
The insect passes
the winter in the egg
Stage in the crevices
of the bark. The
eggs hatch in the
spring and the young
aphids at first are
Sale green in color,
but as they feed they
turn a darker green
and the adults have a
series of large black
tubercles or spots on
the back and sides.
The adults are very
.. active. These aphids
are not found
in crowded colonies.
They feed on both
sides of the leaves
and seem to prefer
S the shaded inner
L parts of the trees.
There may be as
Fig. 11.-Pecan leaflet injured by the black
pecan aphid. many as 15 genera-







Insects and Diseases of the Pecan in Florida


tions of females during the season, all of which produce living
young except the last fall generation, which includes both males
and females, the latter laying eggs for the overwintering gen-
eration.
Control.-The black pecan aphid can be effectively controlled
by thorough spraying with parathion wettable powder 2 pounds
15 percent or equivalent per 100 gallons water, or combined with
bordeaux mixture or ziram used to control pecan scab. Where
serious aphid injury has been experienced the first application
should be made soon after the first yellow spots appear on the
leaves. Repeat applications as needed.
FALL WEBWORM
The fall webworm, Hyphantria cunea (Drury), is perhaps the
most conspicuous pecan insect, as the larvae form the familiar
and unsightly webs over the twigs and foliage (Fig. 12). The
adult moth is about an inch across when the wings are spread,
usually pure white but sometimes with black or brown spots on
the wings. The eggs are deposited in masses on the leaves and
hatch in about a week. The larvae feed in colonies on the leaves
within the web. When they need additional food the web is
enlarged. When full grown, the larvae are more than an inch
long and covered with white and black hairs.
In Florida there are two broods a year of the webworm. Moths
of the first brood appear in April and May, the second during
the middle of summer. Larvae of the second brood feed during
summer and fall. The webworm passes the winter in the pupal
stage in a cocoon under loose rubbish on the ground or just
below the surface of the soil.
Control.-Spraying with either 2 pounds 50 percent DDT wet-
table powder or 2 pounds 15 percent parathion wettable powder
per 100 gallons water, or in combination with bordeaux mixture
or ziram used for scab control, will give effective control of this
insect. In severe infestations it may be necessary to make two
applications of spray material, one for each brood. When the
insects are not very abundant they may be controlled by de-
stroying the webs with the larvae in them. The webs may be
removed from the trees with a long bamboo pole or long-handled
tree pruner.
WALNUT CATERPILLAR
In Florida the walnut caterpillar, Datana integerrima G, &
R., is a major pest during some seasons.







Insects and Diseases of the Pecan in Florida


tions of females during the season, all of which produce living
young except the last fall generation, which includes both males
and females, the latter laying eggs for the overwintering gen-
eration.
Control.-The black pecan aphid can be effectively controlled
by thorough spraying with parathion wettable powder 2 pounds
15 percent or equivalent per 100 gallons water, or combined with
bordeaux mixture or ziram used to control pecan scab. Where
serious aphid injury has been experienced the first application
should be made soon after the first yellow spots appear on the
leaves. Repeat applications as needed.
FALL WEBWORM
The fall webworm, Hyphantria cunea (Drury), is perhaps the
most conspicuous pecan insect, as the larvae form the familiar
and unsightly webs over the twigs and foliage (Fig. 12). The
adult moth is about an inch across when the wings are spread,
usually pure white but sometimes with black or brown spots on
the wings. The eggs are deposited in masses on the leaves and
hatch in about a week. The larvae feed in colonies on the leaves
within the web. When they need additional food the web is
enlarged. When full grown, the larvae are more than an inch
long and covered with white and black hairs.
In Florida there are two broods a year of the webworm. Moths
of the first brood appear in April and May, the second during
the middle of summer. Larvae of the second brood feed during
summer and fall. The webworm passes the winter in the pupal
stage in a cocoon under loose rubbish on the ground or just
below the surface of the soil.
Control.-Spraying with either 2 pounds 50 percent DDT wet-
table powder or 2 pounds 15 percent parathion wettable powder
per 100 gallons water, or in combination with bordeaux mixture
or ziram used for scab control, will give effective control of this
insect. In severe infestations it may be necessary to make two
applications of spray material, one for each brood. When the
insects are not very abundant they may be controlled by de-
stroying the webs with the larvae in them. The webs may be
removed from the trees with a long bamboo pole or long-handled
tree pruner.
WALNUT CATERPILLAR
In Florida the walnut caterpillar, Datana integerrima G, &
R., is a major pest during some seasons.







Florida Agricultural Experiment Stations


There are two generations of this insect in Florida. The
moths from the overwintering pupae emerge from the ground
from the middle of April to the middle of July. The eggs are
laid in masses on the under sides of leaflets and hatch in about
a week. The larvae feed in colonies but do not form a web over

r -- I


Fig. 12.-Young pecan tree defoliated by fall webworm.







Insects and Diseases of the Pecan in Florida


the leaves (Fig. 13). When molting, the larvae crawl to the
trunk or larger limbs (Fig. 14), where each sheds its skin. After
molting they return to the upper branches and continue feeding.
The caterpillars feed for 25 days or longer and when full grown


Fig. 13.-Colony of walnut caterpillars on pecan shoot.







Florida Agricultural Experiment Stations


they crawl down and enter the soil to pupate. Development of
the second brood is similar to that of the first and late in the
fall the larvae enter the soil, where they pass the winter as pupae.
Control.-The same spray treatment should be used as for
control of the fall webworm, or the colonies of caterpillars may
be removed from the
trees and destroyed
by crushing or burn-
ing. They are easily
destroyed when
found massed on the
tree trunks in the act
of molting.
TWIG GIRDLER
S t h The twig girdler,
r nOncideres cintgulatus
(Say), is probably
complained of more
than any other pecan
insect, because of its
habit of cutting off
the twigs during the
late summer and fall.
When the girdlers
are abundant they
may cause serious
damage. Large num-
bers of twigs have
been counted under
a single tree and
many of them had
1 ,clusters of immature
nuts attached (Fig.
Fig. 14.---Larvae of walnut caterpillar prior to 15) The severing of
molting on trunk of pecan tree.
so many twigs also
greatly reduces the fruiting area of the tree for the following
year or more. Pecan nurseries also may suffer heavy losses if
adjacent to heavily infested areas. The twig girdler attacks a
large number of trees and shrubs, including "Australian pine"
(not a true pine), hackberry and cajuput tree, but it is especially
bad on pecan, hickory and persimmon.
Adult beetles (Fig. 16) range in length from '/2 to 8% inch,








Insects and Diseases of the Pecan in Florida


D. r- .. SO
*V- L4--_- 7v


Fig. 15.-Twigs cut off of a single tree by the twig girdler.

and are grayish brown and rather inconspicuous on the trees,
owing to this coloring. The beetles appear in pecan orchards
the latter part of August. Twigs are girdled to provide proper
conditions for the development of the larvae, which are unable
to subsist on wood containing sap. The eggs are always de-
posited in the severed portion of the twig. They hatch in about
three weeks but the larvae grow very little during fall and
winter. In the spring the larvae grow rapidly and complete their








Florida Agricultural Experiment Stations


transformation to adult beetles in the twigs by the latter part
of August.
Control.-Use either 4 pounds 50 percent DDT wettable pow-
der or 3 pounds 15 percent parathion wettable powder per 100
gallons water. Make first application last week in August and
follow with two more applications at two or three-week intervals.
A simple and effective method of controlling the twig girdler
is to gather and burn the severed branches during fall and
winter. Take special care to collect all branches on the ground
as well as those lodged in the trees. If there are hickory or per-
simmon trees adjacent to the pecan orchard, destroy the severed
branches from these also.


Fig. 16.-Adult, or beetle, of the twig girdler at work on a persimmon
branch. Girdler more than twice natural size.

PECAN BUDMOTH
The pecan budmoth, Gretchena bolliana (Sling.), sometimes
causes considerable damage to pecan nursery stock. The larvae
feed on and in the terminal buds of the young trees, causing
excessive branching and stunted growth. This insect causes
very little damage in bearing orchards.
This insect passes the winter as a moth, which is gray with


.^*;r







Insects and Diseases of the Pecan in Florida


blackish-brown patches and about 2/8 inch across the expanded
wings. When the buds begin to open the overwintered moths
lay their eggs on the twigs near the buds. Moths of later gen-
erations lay their eggs on the leaves. There are probably five
or six generations in one season.
Control.-Young nursery trees should be kept in a vigorous
growing condition by proper cultivation and fertilization. Vig-
orously growing trees unfold their buds rapidly and this helps
to prevent the larvae from causing serious damage.
Spraying with either 2 pounds DDT 50 percent wettable pow-
der or 2 pounds 15 percent parathion wettable powder per 100
gallons water or in combination with bordeaux mixture or ziram
as used for control of nursery blight will help to keep this insect
under control. Four or five applications of this spray should
be made at intervals of about three weeks.
PECAN NURSERY CASEBEARER
The pecan nursery casebearer, Acrobasis caryivorella Rago-
not, is found chiefly on pecan nursery stock and in northern
Florida it causes considerable damage in nurseries. The feed-
ing on and in the buds of the young trees is very similar to
that of the pecan budmoth. This casebearer also feed1- on the
foliage of bearing trees but, like the budmoth, causes very little
damage to such trees.
Like the other casebearers, these insects pass the winter as
partly grown larvae in hibernacula. However, the overwinter-
ing larvae and hibernacula are more than twice the size of those
of either the nut casebearer or leaf casebearer. In the nursery
the larvae emerge in the early spring sand feed in the buds and
on the leaves until full grown, when they pupate in a cocoon
in the leaves folded up in the top of the young nursery tree. The
moths are dark grayish with some light spots on the wings.
They are much larger than those of the nut casebearer or leaf
casebearer. There are probably three or four generations in
one season.
Control.-The same nursery practices and control measures
recommended for the pecan budmoth should control this case-
bearer.
PECAN PHYLLOXERA
The injury caused by the pecan phylloxera, Phylloxera de-
vastatrix Perg., and related species is usually not very serious
in Florida, although sometimes it is very conspicuous. The







Insects and Diseases of the Pecan in Florida


blackish-brown patches and about 2/8 inch across the expanded
wings. When the buds begin to open the overwintered moths
lay their eggs on the twigs near the buds. Moths of later gen-
erations lay their eggs on the leaves. There are probably five
or six generations in one season.
Control.-Young nursery trees should be kept in a vigorous
growing condition by proper cultivation and fertilization. Vig-
orously growing trees unfold their buds rapidly and this helps
to prevent the larvae from causing serious damage.
Spraying with either 2 pounds DDT 50 percent wettable pow-
der or 2 pounds 15 percent parathion wettable powder per 100
gallons water or in combination with bordeaux mixture or ziram
as used for control of nursery blight will help to keep this insect
under control. Four or five applications of this spray should
be made at intervals of about three weeks.
PECAN NURSERY CASEBEARER
The pecan nursery casebearer, Acrobasis caryivorella Rago-
not, is found chiefly on pecan nursery stock and in northern
Florida it causes considerable damage in nurseries. The feed-
ing on and in the buds of the young trees is very similar to
that of the pecan budmoth. This casebearer also feed1- on the
foliage of bearing trees but, like the budmoth, causes very little
damage to such trees.
Like the other casebearers, these insects pass the winter as
partly grown larvae in hibernacula. However, the overwinter-
ing larvae and hibernacula are more than twice the size of those
of either the nut casebearer or leaf casebearer. In the nursery
the larvae emerge in the early spring sand feed in the buds and
on the leaves until full grown, when they pupate in a cocoon
in the leaves folded up in the top of the young nursery tree. The
moths are dark grayish with some light spots on the wings.
They are much larger than those of the nut casebearer or leaf
casebearer. There are probably three or four generations in
one season.
Control.-The same nursery practices and control measures
recommended for the pecan budmoth should control this case-
bearer.
PECAN PHYLLOXERA
The injury caused by the pecan phylloxera, Phylloxera de-
vastatrix Perg., and related species is usually not very serious
in Florida, although sometimes it is very conspicuous. The






26 Florida Agricultural Experiment Stations


'U


Fig. 17.-Galls of phylloxera on pecan shoot and leaves.







Insects and Diseases of the Pecan in Florida


galls or tumor-like swellings (Fig. 17) are often seen on the
current season's growth of either seedling or improved varieties
of the pecan, and also on various species of hickory. The phyl-
loxera which causes these galls is a very small insect closely
related to the aphids or plant lice.
This insect passes the winter in the egg stage in protected
places on the branches. The young appear in the early spring,
about the time the buds unfold, and insert their beaks into the
new growth. Their feeding seems to stimulate the growth of
a gall which soon covers the insect. The insect develops in the
gall and lays a large number of eggs and then dies. When the
nymphs that hatch from the eggs develop into adults the gall
splits open and releases them.
Control.-A spray mixture containing 13 fluid ounces of nico-
tine sulfate to 100 gallons of water, with the addition of 21/
gallons of liquid lime-sulfur for control of heavy infestations,
has been successfully used against this insect. For light to
moderate infestations the 13 ounces of nicotine plus 2 quarts
of summer oil emulsion per 100 gallons of water is effective.
These sprays should be applied during the late dormant period,
just as the buds begin to swell.
PECAN CIGAR CASEBEARER
The pecan cigar casebearer, Coleophora caryaefolialla (Clem.),
although usually considered a minor pest, sometimes causes
serious damage to pecans, especially in the western part of the
State. This insect passes the winter as a partly grown larva
in a light-brown case resembling a miniature cigar, usually at-
tached to twigs and limbs. The larvae become active in the
spring about the time the buds open and feed on the buds
and foliage (Fig. 18) until about the middle of May. The adults
appear during the latter part of May and first of June and lay
their eggs on the leaves. There may be several generations
during the season.
Control-If this casebearer requires control measures, spray-
ing in the spring with either DDT or parathion as recommended
for nut casebearer or leaf casebearer will give effective control.

MAY BEETLES
May beetles, Phyllophaga spp. and Anomala spp., also com-
monly called "June bugs," are leaf-feeding insects which may
cause serious defoliation of young pecan trees in early spring.







Insects and Diseases of the Pecan in Florida


galls or tumor-like swellings (Fig. 17) are often seen on the
current season's growth of either seedling or improved varieties
of the pecan, and also on various species of hickory. The phyl-
loxera which causes these galls is a very small insect closely
related to the aphids or plant lice.
This insect passes the winter in the egg stage in protected
places on the branches. The young appear in the early spring,
about the time the buds unfold, and insert their beaks into the
new growth. Their feeding seems to stimulate the growth of
a gall which soon covers the insect. The insect develops in the
gall and lays a large number of eggs and then dies. When the
nymphs that hatch from the eggs develop into adults the gall
splits open and releases them.
Control.-A spray mixture containing 13 fluid ounces of nico-
tine sulfate to 100 gallons of water, with the addition of 21/
gallons of liquid lime-sulfur for control of heavy infestations,
has been successfully used against this insect. For light to
moderate infestations the 13 ounces of nicotine plus 2 quarts
of summer oil emulsion per 100 gallons of water is effective.
These sprays should be applied during the late dormant period,
just as the buds begin to swell.
PECAN CIGAR CASEBEARER
The pecan cigar casebearer, Coleophora caryaefolialla (Clem.),
although usually considered a minor pest, sometimes causes
serious damage to pecans, especially in the western part of the
State. This insect passes the winter as a partly grown larva
in a light-brown case resembling a miniature cigar, usually at-
tached to twigs and limbs. The larvae become active in the
spring about the time the buds open and feed on the buds
and foliage (Fig. 18) until about the middle of May. The adults
appear during the latter part of May and first of June and lay
their eggs on the leaves. There may be several generations
during the season.
Control-If this casebearer requires control measures, spray-
ing in the spring with either DDT or parathion as recommended
for nut casebearer or leaf casebearer will give effective control.

MAY BEETLES
May beetles, Phyllophaga spp. and Anomala spp., also com-
monly called "June bugs," are leaf-feeding insects which may
cause serious defoliation of young pecan trees in early spring.







Florida Agricultural Experiment Stations


Trees near grass or other uncultivated land usually are injured
most. The adults feed only at night.


The adult beetles (Fig. 19) are robu


Fig. 18.-Pecan leaflets injured by larvae of
the pecan cigar casebearer.


st, of a brown color, and
vary in size. The
larvae are the well-
known white grubs
that feed in the soil
upon the roots of
pl a n t s, especially
grasses. Two or
more years usually
are required for lar-
val development.
Control.-The bee-
tles may be removed
from small trees at
night by collecting
them and dropping
them in a pail of ker-
osene or by jarring
them onto a sheet on
the ground and then
destroying them.
Either 2 pounds
DDT 50 percent wet-
table powder or 2
pounds parathion 15
percent wettable


Fig. 19.-Adult May beetles (about 11/ times natural size).







Insects and Diseases of the Pecan in Florida


powder per 100 gallons water, applied early in the period of
flight, will control the beetles.
SPITTLE BUG
The spittle bug, Clastoptera obtusa (Say), is very common
on pecans in northern Florida during the early spring and sum-
mer. The presence of the froth-like material about the buds or
young pecans, in which from one to four or five small insects or
spittle bugs may be found, often causes many inquiries from
growers. This white substance probably serves as a protection
for the young or nymphs from parasites and other insect ene-
mies. The adult spittle bugs are commonly called frog-hoppers
and are usually found wandering around on shrubs and trees.
Numerous observations have failed, thus far, to show any
evidence of serious injury to pecans caused by thi insect.
Control.-Where the spittle bugs are abundant and control is
desired, 2 pounds parathion 15 percent wettable powder per 100
gallons water applied in the middle of May will control this in-
sect. The parathion may be added to the second application of
fungicide spray used for control of scab.
FLATHEADED APPLE TREE BORER
The flatheaded apple tree borer, Chrysobothris femorata
(Oliv.), attacks many kinds of deciduous trees as well as the
pecan. The injury results from the tunnelling of the borer
grubs in the bark and sapwood of the trunk and larger branches
(Fig. 20). Generally it is previously weakened trees that suffer
most from this insect, although vigorously growing trees some-
times become infested. Trees that have been injured in culti-
vation or affected by sunscald and winter injury are usually
very susceptible to attacks of this borer. The borers usually
begin work on the south or southwest side of the trunk and
most of the damage is found in this, area.
The adult beetle is bright copper colored andmay be found
in pecan orchards from prying to late fail. The eggs are laid on
the sun-exposed side of the tree in cracks in the bark or injured
places on the tree. The larvae or borers are creamy white and
are easily recognized by the greatly enlarged and flattened head.
When full grown the borer is about one inch long. There is only
one generation of this beetle a year.
Control.-Remove borers from their burrows with a knife,
taking care to injure the healthy bark as little as possible.
Paint exposed woody parts with a prepared pruning compound







Insects and Diseases of the Pecan in Florida


powder per 100 gallons water, applied early in the period of
flight, will control the beetles.
SPITTLE BUG
The spittle bug, Clastoptera obtusa (Say), is very common
on pecans in northern Florida during the early spring and sum-
mer. The presence of the froth-like material about the buds or
young pecans, in which from one to four or five small insects or
spittle bugs may be found, often causes many inquiries from
growers. This white substance probably serves as a protection
for the young or nymphs from parasites and other insect ene-
mies. The adult spittle bugs are commonly called frog-hoppers
and are usually found wandering around on shrubs and trees.
Numerous observations have failed, thus far, to show any
evidence of serious injury to pecans caused by thi insect.
Control.-Where the spittle bugs are abundant and control is
desired, 2 pounds parathion 15 percent wettable powder per 100
gallons water applied in the middle of May will control this in-
sect. The parathion may be added to the second application of
fungicide spray used for control of scab.
FLATHEADED APPLE TREE BORER
The flatheaded apple tree borer, Chrysobothris femorata
(Oliv.), attacks many kinds of deciduous trees as well as the
pecan. The injury results from the tunnelling of the borer
grubs in the bark and sapwood of the trunk and larger branches
(Fig. 20). Generally it is previously weakened trees that suffer
most from this insect, although vigorously growing trees some-
times become infested. Trees that have been injured in culti-
vation or affected by sunscald and winter injury are usually
very susceptible to attacks of this borer. The borers usually
begin work on the south or southwest side of the trunk and
most of the damage is found in this, area.
The adult beetle is bright copper colored andmay be found
in pecan orchards from prying to late fail. The eggs are laid on
the sun-exposed side of the tree in cracks in the bark or injured
places on the tree. The larvae or borers are creamy white and
are easily recognized by the greatly enlarged and flattened head.
When full grown the borer is about one inch long. There is only
one generation of this beetle a year.
Control.-Remove borers from their burrows with a knife,
taking care to injure the healthy bark as little as possible.
Paint exposed woody parts with a prepared pruning compound








Florida Agricultural Experiment Stations


Fig. 20.-Pupa and larval burrow of the flatheaded apple tree borer in
the trunk of a young pecan tree.








Insects and Diseases of the Pecan in Florida


or with a mixture of
1 part creosote and
3 parts coal tar.
Newly transplant-
ed trees should be
given the best pos-
sible care until well
established. Proper
practices of cultiva-
tion, fertilization and
pruning are impor-
tant. Normally vig-
orous trees with low
heads rarely suffer
severe injury from
this insect.
Preventive meas-
ures include wrap-
ping the trunks of
young trees with
heavy paper or bur-
lap during the period
March to November
to prevent egg lay-
ing. Trap logs may
be used in heavily
infested orchards.
These consist of new-
ly cut logs of pecan,
hickory or oak placed
at intervals in the or-
chard to attract the
egg-laying beetles to
the dying wood,
which they prefer.
These logs should be
placed in the orchard
in early spring and
destroyed the follow-
ing winter. Logs or
prunings should


14


-Exit holes of adult beetles of the red-
shouldered shot-hole borer.








Florida Agricultural Experiment Stations


never be left lying about in the orchard from one season to
another. Fastening a board to the south side of a tree often
is effective.
RED-SHOULDERED SHOT-HOLE BORER
This insect, Xylobiops basilare (Say), attacks only trees or
parts of trees that have been injured or are dying. It makes
small round holes in the bark of the pecan and other trees (Fig.
21). There are several other similar species of shot-hole borers
that also attack devitalized trees.
Control.-Trees should be kept in a healthy growing condi-
tion, as these insects do not often attack healthy wood. Remove
all dead limbs and dying pecan trees and reduce as far as pos-
sible all sources of infestation near the orchard.
TERMITES
Termites, more commonly known as wood lice or white ants,
usually live in dead wood and many growers never think of them
as an insect pest of the pecan. However, pecan nursery stock
and small trees are sometimes killed by the feeding of the ter-
mites in the roots. Trees planted on recently cleared land con-
taining stumps and dead roots are most likely to be injured. The
termiitt~ attack the trees underground and affected trees may
show no signs of injury until they are seriously damaged or die.
The tree may have the taproot or its branches tunnelled until
only a shell or the bark remains.
Control.-Recently cleared land should not be used for a pecan
nursery or orchard until all dead wood and stumps are removed.
Only termite-resistant stakes as iron, heart pine or wood treated
with creosote should be used near newly planted trees, as the
stakes might become infested and the termites spread to the
trees.
HICKORY HORNED DEVIL (REGAL MOTH)
Although the hickory horned devil, Citheronia regalis (F.),
is a very minor pecan pest, many inquiries are received concern-
ing it. This large' caterpillar (Fig. 22) is the larva of the regal
moth, the largest and most magnificent of the royal moths (Fig.
23). The fore wings of the moth are olive colored, spotted with
yellow, and the hind wings are orange red, spotted with yellow.
The larva is our largest caterpillar and can be easily recog-
nized by the large spiny horns with which it is armed. It feeds
on various trees and shrubs, never becomes very numerous.








Florida Agricultural Experiment Stations


never be left lying about in the orchard from one season to
another. Fastening a board to the south side of a tree often
is effective.
RED-SHOULDERED SHOT-HOLE BORER
This insect, Xylobiops basilare (Say), attacks only trees or
parts of trees that have been injured or are dying. It makes
small round holes in the bark of the pecan and other trees (Fig.
21). There are several other similar species of shot-hole borers
that also attack devitalized trees.
Control.-Trees should be kept in a healthy growing condi-
tion, as these insects do not often attack healthy wood. Remove
all dead limbs and dying pecan trees and reduce as far as pos-
sible all sources of infestation near the orchard.
TERMITES
Termites, more commonly known as wood lice or white ants,
usually live in dead wood and many growers never think of them
as an insect pest of the pecan. However, pecan nursery stock
and small trees are sometimes killed by the feeding of the ter-
mites in the roots. Trees planted on recently cleared land con-
taining stumps and dead roots are most likely to be injured. The
termiitt~ attack the trees underground and affected trees may
show no signs of injury until they are seriously damaged or die.
The tree may have the taproot or its branches tunnelled until
only a shell or the bark remains.
Control.-Recently cleared land should not be used for a pecan
nursery or orchard until all dead wood and stumps are removed.
Only termite-resistant stakes as iron, heart pine or wood treated
with creosote should be used near newly planted trees, as the
stakes might become infested and the termites spread to the
trees.
HICKORY HORNED DEVIL (REGAL MOTH)
Although the hickory horned devil, Citheronia regalis (F.),
is a very minor pecan pest, many inquiries are received concern-
ing it. This large' caterpillar (Fig. 22) is the larva of the regal
moth, the largest and most magnificent of the royal moths (Fig.
23). The fore wings of the moth are olive colored, spotted with
yellow, and the hind wings are orange red, spotted with yellow.
The larva is our largest caterpillar and can be easily recog-
nized by the large spiny horns with which it is armed. It feeds
on various trees and shrubs, never becomes very numerous.







Insects and Diseases of the Pecan in Florida 33

Control.-Control measures are rarely required for this insect
on pecans. When the larvae are found they may be removed
by hand and destroyed. In spite of their appearance they will


.f


No<.-. -LIA* - ;* *i ,


Fig. 22.-Larva of the regal moth, commonly called "hickory horned devil."


Fig. 23.-Adult of the regal moth (male).


*bib s


~Cc~Z


il~, k~"ZU








Florida Agricultural Experiment Stations


do no harm to one handling them. If necessary, DDT or para-
thion may be applied as for control of the fall webworm when


the larvae are small.


PECAN WEEVIL
The pecan weevil,
C u r c u I o caryae
(Horn), is a very de-
structive pest of pe-
cans and hickories in
some areas, though
_- it apparently has
0 been of minor impor-
tance in Florida. It
'-x has caused heavy
damage to pecans in
other Southern states
Sfor a number of
years but it was not
S known to occur in
this State prior to
left, fe- 1945. Since then it
ize.
has been found in
several localities in Jefferson,


Leon, Gadsden, Jackson, Cal-
houn and Santa Rosa counties.
Spread of the weevil may be
rather slow, as the adults usu-
ally do not go far from the tree
where they develop. When the
adults emerge from the soil
they tend to go to the nearest
trees and if there are nuts on
the trees the insects remain
there to feed and to lay eggs.
SThe life history of the weevil
has not been studied thorough-
Fig. 25.-Grubs or larvae of the ly in Florida but it is known
pecan weevil within nut and emer- that the complete life cycle re-
gence holes where weevil grubs left that the complete life cycle re-
nut. quires two or three years. It
is thought that the adults (Fig.
24) begin to emerge about the first of July and continue to ap-
pear through the summer. The time of egg laying depends on
the stage of development of the pecan nuts, as eggs are not laid


4( f.
I 1l


N.


Fig. 24.-Adult pecan weevils, male
male right, 21/ times natural s:







Insects and Diseases of the Pecan in Florida


until the nut kernels have hardened. This will vary with season,
locality and variety of pecan. The female weevil uses the long
beak to make a puncture through the shuck and shell of the
nut and then lays an egg in this opening. The grubs or larvae
(Fig. 25) hatching from the eggs feed on the kernels and become
fully grown in a few weeks. They then make circular holes
(Fig. 25) through the side of the nuts. They emerge through
these holes, drop to the ground and enter the soil to a depth
of four to 12 inches. There they make earthen cells in which
they pupate. Pupation may occur that same fall or it may be
delayed until the second fall after they enter the soil. The adult
weevils emerge from the soil during the summer following pupa-
tion.
The pecan weevil is responsible for two distinct types of
damage. During July and August before the shells have hard-
ened the adult weevils make feeding punctures in the nuts. These
punctures cause the nuts to drop from the trees and the entire
crop may be destroyed if the weevils are numerous and the crop
is light. If there is a good crop on the trees this damage may
not be noticed or it may be attributed to other causes.
The second type of damage is caused by the grubs in the nuts.
At harvest time the infested nuts may contain one or more of
the white, legless grubs or, if the grubs have already emerged
to pupate, there will be circular holes about 1/ inch across in
the shell. Infested nuts are entirely worthless, as the grubs
cause complete destruction of the kernels and in addition the
shucks may stick tight to the shells.
Pecan varieties differ widely in susceptibility to attack by
the weevil. Early maturing varieties generally are most heavily
infested, while late varieties suffer less damage. Most species
of hickory nuts are infested in areas where the weevil is found.
Control.-DDT is an effective insecticide for control of the
pecan weevil. Use six pounds of 50 percent DDT wettable pow-
der, or equivalent, per 100 gallons of water. If either bordeaux
mixture or ziram is used for control of pecan scab, the DDT
may be combined with the fourth and fifth fungicide applica-
tions.
The insecticide applications should be timed to correspond
with the emergence of the adult weevils. Only in this way can
feeding of the weevils and dropping of the nuts be prevented.
The first application should be made when six or more weevils








Florida Agricultural Experiment Stations


are found on any tree known to have been infested in previous
years. The second application should be made 10 to 14 days
later.
When an infested tree is jarred the adult weevils drop to the
ground, where they lie motionless and apparently lifeless for a
few minutes. Advantage may be taken of this habit to deter-
mine when to begin the spray applications. Place regular pick-
ing or harvesting sheets under the tree to be examined for
weevils. Then jar each limb lightly two or three times with a
padded pole or climb the tree and jar the limbs with the foot.
Collect the weevils from the sheets and count them. When six
or more weevils are jarred from a tree it is time to make the
first insecticide application.
If one has only a few pecan trees it is possible to reduce weevil
damage about 50 percent by jarring the trees and collecting the
weevils at weekly intervals during the period of adult activity,
which usually lasts from the first of July to the middle of Sep-
tember. To save unnecessary work it is a good policy to jar
only one or two trees known to have been heavily infested the
year before until weevils begin to appear. During the succeed-
ing weeks all of the trees should be shaken. Regular harvesting
sheets are spread under the trees while they are jarred and the
collected weevils may be killed by dropping them into a can
containing kerosene.
In weevil-infested orchards the pecans should be harvested as
early as possible and special care must be taken to gather all
of the nuts, both good and bad. The nuts should be sorted
immediately and all faulty ones burned or otherwise destroyed
so that any remaining weevil grubs will be killed.

MITES
The mite, Tetranychus hicoriae McGregor, caused serious in-
jury to pecan foliage and premature defoliation in orchards near
Monticello, Florida, in June 1947. Since that time it has been
reported as causing injury to pecan foliage in almost every sec-
tion of the pecan-growing area of the State. This mite has also
been reported causing serious injury to pecan foliage in other
Southern states. It was also collected in 1948 near Marianna,
Florida, on water hickory, Carya aquatic Michx f. Nutt.
Observations indicate that the life history of this mite is very
similar to that of the common two-spotted spider mite, Tetra-
nychus bimaculatus Harvey. It is possible that damage to pecan







Insects and Diseases ;of th, Pecan in Florida


foliage attributed to the two-spotted spider mite in the past was
actually caused by the new species.
An infestation generally starts on the lower branches of the
pecan tree and spreads upward. The feeding of large numbers
of these mites causes a characteristic type of foliage injury.
The infested leaflets first show a light-brown discoloration along
the midrib, where the mites start to feed. As the mites and
injury increase on the leaflet, the discoloration spreads outward
and the leaflet looks as if it had been scorched by fire. Severely
injured leaflets drop off and excessive premature defoliation may
occur. Since this mite has the ability under favorable conditions
to increase its numbers rapidly to a level that will result in se-
vere defoliation of pecan trees, growers should be familiar with
the type of injury and know when to apply control measures.
Observations have indicated that the use of DDT for control
of the nut casebearer and other pecan insects has caused abnor-
mal increases in
m i t e population.
However, severe in-
festation of mites
may appear on un-
sprayed foliage.
Control. Para-
thion is very effec-
tive against mites
present at time of
application and pos-
sibly against newly
hatched crawlers
for three to four
days. However, mite
population can build
up rapidly through
hatching of eggs
following a single
s p r a y application.
Use 2 pounds of 15
percent parathion
wettable powder, or
equivalent, per 100
Fig. 26.-Full-grown larva of Catocala maes-
gallons water or tosa, about 2A natural size.







Florida Agricultural Experiment Stations


in combination with either bordeaux mixture or ziram applied
for scab control. Make first application when leaf scorch con-
dition caused by mite injury appears on foliage. Repeat appli-
cation in six to eight days.
PECAN CATOCALA
Several species of catocala may be found destroying pecan
foliage in the spring. When abundant, these caterpillars are
capable of doing considerable damage by stripping the leaves
until only the petioles and stems remain. The caterpillar (Fig.
26) of Catocala maestosa Hlst. is dark grey in color and when
full grown may be more than three inches in length. They hide
by day in the crevices of the bark. Their color so closely re-
sembles that of the bark that
they often escape observation.
Due to the size and leathery-
looking skin of these caterpil-
lars, they are often called "alli-
gator worms."
These insects pass the winter
in the egg stage on the under
side of the bark scales. The
eggs hatch in the spring and the
caterpillars feed on the foliage
Fig. 27.-Adult of Catocala maes- caterpillars feed on the foliage
tosa, about 1/ natural size. during spring and early sum-
mer. The moths (Fig. 27) ap-
pear as early as the latter part of June and may continue to
emerge until late fall.
Control.-Insecticides applied for control of either the first
generation nut casebearer or the leaf casebearer in May will also
control the caterpillars of the pecan catocala. If these insects
become abundant enough to require special control measures,
apply either DDT or parathion as recommended for nut case-
bearer control.
DISEASES OF THE PECAN
Three classes of diseases and one of injuries now seriously
affecting pecans in Florida are: (1) fungous, (2) bacterial, (3)
nutritional, and (4) injuries due to environment. The first two
are caused by specific organisms, the third is caused by a defi-
ciency of one or more mineral elements, and the fourth is com-
posed of injuries due to climatic conditions.







Florida Agricultural Experiment Stations


in combination with either bordeaux mixture or ziram applied
for scab control. Make first application when leaf scorch con-
dition caused by mite injury appears on foliage. Repeat appli-
cation in six to eight days.
PECAN CATOCALA
Several species of catocala may be found destroying pecan
foliage in the spring. When abundant, these caterpillars are
capable of doing considerable damage by stripping the leaves
until only the petioles and stems remain. The caterpillar (Fig.
26) of Catocala maestosa Hlst. is dark grey in color and when
full grown may be more than three inches in length. They hide
by day in the crevices of the bark. Their color so closely re-
sembles that of the bark that
they often escape observation.
Due to the size and leathery-
looking skin of these caterpil-
lars, they are often called "alli-
gator worms."
These insects pass the winter
in the egg stage on the under
side of the bark scales. The
eggs hatch in the spring and the
caterpillars feed on the foliage
Fig. 27.-Adult of Catocala maes- caterpillars feed on the foliage
tosa, about 1/ natural size. during spring and early sum-
mer. The moths (Fig. 27) ap-
pear as early as the latter part of June and may continue to
emerge until late fall.
Control.-Insecticides applied for control of either the first
generation nut casebearer or the leaf casebearer in May will also
control the caterpillars of the pecan catocala. If these insects
become abundant enough to require special control measures,
apply either DDT or parathion as recommended for nut case-
bearer control.
DISEASES OF THE PECAN
Three classes of diseases and one of injuries now seriously
affecting pecans in Florida are: (1) fungous, (2) bacterial, (3)
nutritional, and (4) injuries due to environment. The first two
are caused by specific organisms, the third is caused by a defi-
ciency of one or more mineral elements, and the fourth is com-
posed of injuries due to climatic conditions.







Insects and Diseases of the Pecan in Florida


DISEASES DUE TO SPECIFIC ORGANISMS
SCAB
Pecan scab, Cladosporium effusum (Wint.) Demaree, is one
of the most important limiting factors in nut production, espe-
cially in the Southeastern states, and its control is of vital im-
portance. The following varieties planted more or less exten-
sively are scabbing in certain orchards in some parts of Florida:
Schley, Success, Mahan, Frotscher, Randall, Kennedy, Money-
maker, Moore, Nel-
son, Teche, Curtis,
Stuart and Elliot. It
now appears prob-
able that all varieties
of pecans will be sus-
ceptible to scab when
proper strains of the
fungus become es-
tablished in an or-
chard. Moneymaker,
Teche, Curtis and
Stuart varieties for-
merly were consid-
ered immune to scab,
but they have been .. .
found to be suscept-
ible in some locali-
ties. However, scab
on Curtis is mostly
confined to young
trees growing in Fig. 28.-Schley nuts that received no spray.
nurseries. The shucks are severely infected with the fungus
causing scab disease and they are opening pre-
The scab fungus maturely.
attacks the rapidly
growing tissues of the leaves, shoots and nuts. When these
tissues cease growing they reach a state of complete immunity.
On highly susceptible varieties such as Schley defoliation often
results, especially when frequent infections occur beginning in
early spring; but greatest damage is to the nuts, losses fre-
quently ranging from 75 to 95%.
The scab fungus is carried over winter in the infected spots
on old leaves and shucks (Fig. 28) and in lesions on the shoots

N







Insects and Diseases of the Pecan in Florida


DISEASES DUE TO SPECIFIC ORGANISMS
SCAB
Pecan scab, Cladosporium effusum (Wint.) Demaree, is one
of the most important limiting factors in nut production, espe-
cially in the Southeastern states, and its control is of vital im-
portance. The following varieties planted more or less exten-
sively are scabbing in certain orchards in some parts of Florida:
Schley, Success, Mahan, Frotscher, Randall, Kennedy, Money-
maker, Moore, Nel-
son, Teche, Curtis,
Stuart and Elliot. It
now appears prob-
able that all varieties
of pecans will be sus-
ceptible to scab when
proper strains of the
fungus become es-
tablished in an or-
chard. Moneymaker,
Teche, Curtis and
Stuart varieties for-
merly were consid-
ered immune to scab,
but they have been .. .
found to be suscept-
ible in some locali-
ties. However, scab
on Curtis is mostly
confined to young
trees growing in Fig. 28.-Schley nuts that received no spray.
nurseries. The shucks are severely infected with the fungus
causing scab disease and they are opening pre-
The scab fungus maturely.
attacks the rapidly
growing tissues of the leaves, shoots and nuts. When these
tissues cease growing they reach a state of complete immunity.
On highly susceptible varieties such as Schley defoliation often
results, especially when frequent infections occur beginning in
early spring; but greatest damage is to the nuts, losses fre-
quently ranging from 75 to 95%.
The scab fungus is carried over winter in the infected spots
on old leaves and shucks (Fig. 28) and in lesions on the shoots

N







Florida Agricultural Experiment Stations


of the trees. In the spring when weather conditions become
favorable the dormant fungus becomes active and produces
spores which are spread to the new leaves, shoots and nuts
where, under suitable conditions, they may cause infections
(Fig. 29).
On varieties very susceptible to scab, such as Schley, the
primary infections on the foliage (Fig. 30) are irregular in out-


Fig. 29.-Early spring infections on Schley variety resulting from scab
carried over on old shucks from the previous season. Some of the leaflets
are infected with the fungus causing scab.








Insects and Diseases of the Pecan in Florida


line and may be followed by some secondary infections. On
varieties more resistant to scab, such as Moore and Stuart, pri-
mary scab infections usually take place relatively late in the
season when the leaves are almost immune; therefore, the infec-
tions are mostly confined to nuts. Occasionally, though, during
ideal scab infection periods in early spring the foliage of these
more resistant varieties does become infected. The spots are


Fig. 30.-Primary scab infections
on foliage of Schley, a variety
highly susceptible to scab in most
localities.


Fig. 31.-Primary scab infections
on foliage of Moore, a variety
highly resistant to scab in most
localities. Scab infections are reg-
ular in outline and occur on foliage
only during very favorable infec-
tion periods in early spring.







Florida Agricultural Experiment Stations


usually regular in outline and are surrounded by a distinct halo
(Fig. 31).
Infection of leaves, shoots and nuts by the scab fungus is cor-
related with rainfall during spring and early summer. Frequent
rains and cloudy weather which keep the leaves wet over night
or for 12 hours or
more favor infection.
Under such condi-
tions initial infec-
-. b tions may occur prior
to the middle of
SApril, and these de-
,velop rapidly. By the
latter part of April
or the first week in
May new crops of
spores are produced
which cause secon-
dary infections un-
der favorable condi-
tions if no spraying
has been done. Rains,
which keep the leaves
and nuts wet for 12
to 18 hours, provide
a condition yery fa-
vorable for infec-
tion, as it requires
Fig. 32.-Schley nuts that received one pre-
pollination spray of 4-1-100 bordeaux mixture, from six to eight
followed by three applications of 6-2-100 bor- hours for the spores
deaux. Photographed latter part of November. to
to germinate and
cause infection. Under these conditions usually it is from one
to two weeks from the time of infection until the scab lesions
may be observed on the new tissue of either leaves or nuts. To
prevent infection or to control scab, old leaves and shucks from
which the spores may be spread should not remain exposed in
the orchard. Furthermore, during rainy periods in early spring
and summer the leaves, shoots and nuts should have a coating
of bordeaux mixture.
The primary infections are first observed as elongated, olive-
brown lesions usually occurring on the veins of the under sides
of the leaves of susceptible varieties. These spots first appear














CLASS 1*
Nuts Grade A








CLASS 2
Nuts Grade A








CLASS 3
Nuts Grade B







CLASS 4
Nuts Grade B







CLASS 5
Nuts dropped
prematurely




Fig. 33.-Practically full grown Schley nuts illustrating degrees of scab in-
fection by classes and their relation to nut grades. Photo made August 1st.


* Definition of each class
Class Amount of infection
1 No infection
2 1-3 initial infections


3 4 or more initial infections
4 Few secondary infections
5 Numerous secondary infections







Florida Agricultural Experiment Stations


as very small pin points but soon enlarge and, with the occur-
rence of secondary infections, may cause areas of the leaves to
appear almost black due to the coalescing of the spots. On the
tnuts the spots of infection are small, black, circular and slightly
raised at first but later may become sunken. Nuts of highly
susceptible varieties may have many infections on them until
practically the whole surface appears black.
Scab injury on Schley nuts is illustrated in Fig. 33 in photo-
graphs made on August 1. Of the five classes of nuts only one,
class 5, are unmarketable but nuts in classes 3 and 4 are poor
in quality.
Untreated, severely infected nuts may drop prematurely or
they may almost entirely stop growth and remain attached to
the shoots indefinitely. On the other hand, nuts sprayed as
recommended usually remain free of scab (Fig. 32).

RECOMMENDATIONS FOR PECAN SCAB CONTROL
Knock off all old shucks and leaf stems before the trees begin
to leaf out in spring. A slight jarring of trees will cause most
old shucks and leaf stems to fall when they are wet after a rain
or on misty or foggy days. It is preferable to bury shucks and
leaves with a turning plow deep enough that they will not be
turned up again by disk harrows or other means of cultivation.
Since most successful orchardists plant winter cover crops in
their orchards, turning under shucks and leaves is not practical.
However, scab spores are washed down by the rain; therefore,
to get shucks and lea\e.% on the ground will assist materially in
preventing foliage infection.
Pruning off low limbs will aid materially in scab control by
letting in sunlight, thereby assisting in better air circulation.

SPRAYING
A large number of fungicides, including various strengths of
bordeaux mixture, insoluble copper compounds, wettable sulfurs,
organic fungicides and ,mercury derivatives have been tested
for the control of pecan scab. Of these the three most effective
(fungicides) are home-made bordeaux mixture, 2-100 ziram
(76%) plus 1/ percent summer oil emulsion and 2-100 zineb
(65%) plus 1 percent summer oil emulsion. When these are
applied according to the schedule given below, the disease can
be controlled with slight or no injury to the trees.
Four spray applications have given satisfactory control of







Insects and Diseases of the Pecan in Florida


pecan scab during the last 16-year period in the latitude of
Albany, Georgia, but, due to wet weather in August and Sep-
tember in some areas in North Florida, this number of applica-
tions has not given control here. For this reason a fifth appli-
cation made the last
week in July or first I ]
week in August is
recommended.
First Application.
-When the leaves
are 1/4 to 1/pp grown
and before pollina-
tion8 a 4-1-100 bor-
deaux mixture is
used. (Instructions
for preparation of
bordeaux mixture
are given on page
70.) In the vicinity
of Monticello, Fla.,
this application
should be made usu-
ally between April 10
and 20.
Fig. 34.-Schley nuts showing results of
Second Application. early spring infection. Secondary infection was
-A 6-2-100 bordeaux prevented by three thorough applications of
6 6-2-100 bordeaux, the last about July 15. Pho-
mixture should be tographed October 1.
applied soon after
pollination is complete, or when the tips of the small nuts have
turned brown.
Third and Fourth Applications.-The third spray application
should be made about three to four weeks after the second, and
the fourth about three to four weeks after the third, using a
6-2-100 bordeaux mixture or 2-100 ziram (76%) plus 1 quart
of summer oil emulsion.'0
Fifth Application.-The fifth spray application should be made
8 Care must be used in making the prepollination spray application since
injury may result to the foliage if the temperature is as low as 50- 550 F.
at the time the spray is applied.
Add 2 pounds 50% wettable DDT or 2 pounds of 15% wettable para-
thion if nut casebearer, Acrobasis caryae Grote, is present.
10 Add 2 pounds 15% wettable parathion for the fourth and fifth spray-
ing if the black aphid, Melanocallis caryaefoliae Davis, is present.







Florida Agricultural Experiment Stations


.the last week in July or first
week in August, using 6-2-100
bordeaux mixture or 2-100
ziram (76%). (See complete
spray schedule on page 76.)
Both timing and thoroughness
of the spray application are very
important. Sometimes weather
conditions are such that it is not
possible to spray at the proper
time to prevent early infection
on the young nuts, but when this
does occur and the trees are
properly sprayed during the
later applications secondary in-
fection can be prevented and
good quality nuts may be pro-
duced (Fig. 34).

DOWNY SPOT
Downy spot, Mycosphaerella
caryigena Demaree & Cole, is a
foliage disease of pecans that
was first observed in south Geor-
gia and north Florida in 1927.
In the vicinity of Monticello,
Fla., the disease may be seen
first during late spring or early
summer as downy or frosty
spots on the lower sides of the
leaves (Fig. 35). This appear-
ance is due to production of
spores by the fungus. Dew, fog
and rain assist in spreading the
Fig. 35.-White or "frosty" spots spores from one leaf to another.
on the under side of a pecan leaf Later, after these spores have
showing characteristic markings of been washed away or hae de-
downy spot disease in the early been washed away or have de-
stages soon after formation of teriorated, greenish-yellow spots
conidiophores and conidia. remain that are clearly visible
on both sides of the leaves. As the season advances the diseased
areas die and some premature defoliation may occur.
The downy spot organism lives over winter in the diseased







Insects and Diseases of the Pecan in Florida


leaves, completing its life cycle in them, and spores from the
perithecial or winter stage are liberated in large quantities the
following spring, thereby infecting the new foliage.
While all varieties are attacked to some extent by the fungus,
Moneymaker and Stuart are most susceptible.
Control. Where winter
cover crops are turned under
about the first of April the
sanitation effects from bury-
ing diseased leaves will be
very beneficial in controlling
downy spot. Since the win-
ter spores of the causal or-
ganism are liberated from
the fruiting bodies in the old
leaves during rainy periods
in spring and since foliation
of most varieties begins at
about that time, plowing un-
der infected leaves will as-
sist materially in reducing
this infection.
Where spraying is done to
control scab the first two
scab applications of bor-
deaux mixture or ziram are
timed to control downy spot
also. In orchards where it is a
not necessary to spray for
scab control the first two ap-
plications in the scab spray
(see page 76) schedule will
control downy spot.

PECAN LEAF BLOTCH
Pecan leaf blotch, Mycos- .....
phaerella dendroides (Cke.)
Demaree & Cole, is a foliage Fig. 36.-Early stage of leaf blotch
on the under side of a leaflet. At this
disease of nursery and or- stage the conidiophores and conidia are
chard trees and is especially in clusters and the pimple-like peri-
thecia are just appearing to form the
prevalent in the vicinity of blotches.







Florida Agricultural Experiment Stations


Monticello. The fruiting bodies first appear on mature leaves
in June or July as olive green velvety tufts of conidiophores
and spores on the under surface, while yellow spots appear later
on the upper surface of the leaves (Fig. 36). Fruiting bodies
of the perfect stage, black pimple-like structures, make their
appearance among the conidiophores about midsummer; and
after the spores have been washed away by rain, or have other-
wise deteriorated, groups of these pimple-like structures unite,
giving the leaves a black, shiny, blotched appearance. Occasion-
ally an entire leaflet is enveloped by coalescence of these blotches
and premature defoliation results.
Control.-Leaf blotch and downy spot are similar in that both
causal organisms overwinter on fallen, decaying leaves. The
same sanitation measures-plowing under old leaves in early
spring-will materially reduce the infection later.
In contrast to the downy spot organism, the leaf blotch patho-
gen is only a weak parasite and does not attack orchard trees
unless they have been lowered in vigor by overcrowding, rosette
or attacks from borers, or have suffered from general neglect.
Nursery trees are more susceptible to attack than old trees and
the disease is especially prevalent where the nursery blight dis-
ease is present. Under such conditions defoliation begins with
the basal leaves and the disease gradually progresses upward
until defoliation is complete with the exception of a few leaves
in the tops of the trees.
Control measures for scab and downy spot will control the
blotch disease also. In localities where only leaf blotch is pres-
ent one application in June of low-lime bordeaux mixture of the
6-2-100 formula will prevent the disease.

BROWN LEAF SPOT
Brown leaf spot, Cercospora fusca Rand, is a disease of minor
importance, especially on healthy, vigorous trees. It is preva-
lent throughout the entire pecan belt, but causes serious pre-
mature defoliation only in localities having a high rainfall and
in orchards where the trees lack vigor as a result of neglect. A
typical diseased leaflet is shown in Figure 37. Primary infec-
tions of the diseased spots are circular in outline, reddish brown,
and often develop grayish concentric zones, while later these
spots are very irregular in outline. Like pecan scab, brown leaf
spot inoculum is carried over winter in infected spots on old
leaves. In Florida the disease first appears in June or July,







Insects and Diseases of the Pecan in Florida


attacks only mature leaves, and if not controlled causes prema-
ture defoliation early in October. Stuart is very susceptible
while all others are more or less resistant, especially if a good
cultural program is followed.
Control.-In spraying for brown leaf spot only one applica-
tion of 6-2-100 bordeaux
mixture made at any time
between May 15 and June 15
usually will be sufficient.

GNOMONIA LEAF SPOT


The gnomonia leaf spot,
Gnomonia dispora Demaree
& Cole, is another pecan dis-
ease of minor importance oc-
casionally observed in Flor-
ida and the southern part of
Georgia. It first appears in
June as a small, inconspicu-
ous brown spot with no defi-
nite diagnostic features. The
spots may enlarge to 1/2 inch
or more in diameter and be-
come almost black. The
shape of the spots varies
from circular to greatly
elongated. The most dis-
tinguishing characteristic of
the gnomonia leaf spot is
that the affected portion is
frequently confined to a nar-
row space between the lat-
eral veinlets, thus forming a
long, narrow, dead area
(Fig. 38). The disease has
not become serious enough
to justify the use of control
measures. So far it has
been found only on rosetted
trees, which suggests that
the fungus causing the spots
is a weak parasite.


- Y --- P


Fig. 37.-Pecan brown leaf spot on
under side of leaf. The diseased spots
are characterized by concentric mark-
ings.






Florida Agricultural Experiment Stations


fit
34
iJrj


L "
Fig. 38.-Gnomonia leaflet spot on pecan. Delimitation of the spots by the
leaflet veins is characteristic of the disease.







Insects and Diseases of the Pecan in Florida


NURSERY BLIGHT
In seasons of excessive rainfall pecan nursery blight, Elsinoe
randii Jenkins & Bitancourt, becomes one of the most important
limiting factors in the production of budded pecan trees, espe-
cially in north Florida. As
its name implies, this disease -.
is confined almost entirely to ,
nursery trees. The fungus
causing it invades both
young and old leaflets, and
infections that are first ob- :
served in April result in I
small reddish lesions that
develop on both surfaces of
the leaves (Fig. 39). Later
the spots on the upper sur-
face of the leaves turn ash-
gray. Single lesions usually
are about 1/8 inch in diame-
ter. These spots, however,
may unite by secondary in-
fections and form a continu-
ous lesion along each side of
a vein. Late season infec-
tions are most numerous
along the midrib and larger
veins. The diseased areas
are soon killed by the invad-
ing fungus, the tissues be-
coming brittle and breaking
out, resulting in ragged mar-
gins and perforations.
Control. Nursery blight
in Florida can be controlled
by applying 4-1-100 bor-
deaux mixture about April
5 to 15, and following this
with three applications of Fig. 39.-Early stages of nursery
with three applications of blight on pecan leaflet.
6-2-100 bordeaux mixture.
These later applications should be made at monthly intervals,
with the last one on or about July 10 (Fig. 40).
Since the disease is carried over winter on fallen leaves in the







Florida Agricultural Experiment Stations


nursery, destroying these old leaves by plowing them under will
aid materially in effecting control.

THREAD BLIGHT
Thread blight, Pellicularia koleroga Cke., attacks pecans and
numerous other woody plants throughout Florida. The fungus
overwinters in compact masses of fungous tissues known as
sclerotia, which adhere to the bark of twigs and leaf petioles
(Fig. 41). The fungus threads or mycelium grows rapidly in
May and June from the sclerotia on the twigs onto the new
petioles and leaflets. In this manner the thread-like mycelium
spreads over the lower surface of the leaves, completely para-
sitizing and killing them (Fig. 42), causing premature defolia-
tion of the affected trees. Under particularly favorable condi-
tions the fungus growing on the leaves produces tiny spores
basidiosporess) which are disseminated by wind, rain and dews.
These spores probably cause infection and explain the wide
spreading of the disease which is sometimes observed, although
little is known about them.
Most common symptom of thread blight during summer is the
matting together of dead leaves. These mats of dead leaves
hang from the shoots by the spider-web-like threads until frost
kills the fungus, allowing the leaves to fall to the ground.

Fig. 40.-Spraying nursery trees with 6-2-100 bordeaux mixture. Monti-
cello, Florida. Approximately 100 gallons of spray material per acre re-
quired for this type of spraying.








Insects and Diseases of the Pecan in Florida


Control.-The thread blight fungus usually attacks pecan
trees near forests or wood lots in which the fungus is present,
and spreads rapidly in damp localities or especially where the
pecan trees are crowded or neglected. Pruning away the lower
limbs and removing trees where they are crowding will assist
in controlling the disease. Where the infection is severe, two
applications of 6-2-100 bordeaux, second and third in the scab
schedule, will prevent or control the disease.
POWDERY MILDEW
Powdery mildew, Microsphaera alni Wint., is of minor im-
portance on pecans in Florida. This disease, like scab, affects
both foliage and nuts, forming a white superficial fungous
































Fig. 41.-Left, compact masses (sclerotia) of the thread blight
fungus on a leaf petiole. Right, similar masses on a twig.







Florida Agricultural Experiment Stations


-~ 1





























Fig. 42.-The thread blight disease on pecan foliage. The leaflets are
withered and discolored.

growth early in the growing season (Fig. 43), generally in July,
while later the perithecial or winter stage develops on the dis-
eased spots. Occasionally premature defoliation occurs under
conditions very favorable for the spread and development of
the fungus. Where the nuts are infected early in the season pre-
mature splitting of the shucks results and this causes shriveled
kernels.







Insects and Diseases of the Pecan in Florida


Control.-Most varieties of pecans grown commercially in
Florida are resistant to mildew, and where this disease is pres-
ent it is easily controlled by making two applications of 6-2-100
bordeaux mixture in June and July (see spray schedule p. 76).
The same sanitary measures as those recommended for scab,
downy spot, leaf blotch and nursery blight also will assist in
controlling powdery mildew.

PINK MOLD
Pink mold, Cephalothecium roseum Corda, is frequently ob-
served during late summer and early fall as a pinkish fun-
gus growth on the
shucks of nuts that
have been attacked
by the scab disease
or where the shuck
has been injured by
mechanical means,
especially insect c t
punctures (Fig. 44).
This pink mold is
caused by a sapro-
phytic fungus that
gains entrance into
the shuck and nuts
through scab spots
or other injury and
continues to develop
after the nuts have
matured. It will
penetrate the shell
and enter the kernel
of thin shell varie- Fig. 43.-Powdery mildew in its early stages
on Farley nuts. The white mycelium has mostly
ties, causing a decay covered the surface of the nuts.
that is known as
"pink rot." Affected nuts leak oil and their shells have an
oiled appearance and often a strong rancid odor.
Control.-Since the pink mold fungus is usually found on
scabby nuts it is most conspicuous on susceptible varieties, such
as Schley, growing in yards where no fungicide was used. A
spray program that controls scab will usually control pink rot.








56 Florida Agricultural Experiment Stations

Some nuts become infected on the tree prior to harvest; after
harvest the mold does not spread from infected to sound nuts.
WOOD ROT
All wounds on pecan trees provide a point of entrance for
wood-rotting fungi unless the injured surfaces are properly
treated. Once these fungi gain entrance they spread quite rap-
idly through the wood and may endanger the entire tree. Some
wounds heal very much more quickly than others. Wounds made
flush with the trunk or main branches heal more quickly than
those even of smaller size that are not flush (Fig. 45). Smooth,
carefully made wounds heal more quickly than those having
rough jagged or irregular surface (Fig. 46).
Wood-rotting fungi usually can be prevented from entering
wounds by painting them once annually with a creosote and
coal tar paint mixture made by adding 1 part of commercial
creosote to 3 parts of coal tar. This mixture is caustic and will
slightly injure the cambium but the wound will generally remain
free of wood-rotting fungi and eventually heal.


Fig. 44.-Early and late development of the pink mold fungus
on Schley pecans.







Insects and Diseases of the Pecan in Florida


Several tree wound paints sold under various trade names,
most of them having asphalt, tar or vegetable gums as their
base, are more expensive and usually do not furnish any better
wound protection than creosote and coal tar.
CROWN GALL
Crown gall, Agrobacterium tumefaciens (E. F. Sm. & Town)
Conn, is a bacterial disease of pecan which does extensive dam-
age under certain conditions. Formerly it was considered a
disease of nursery trees only (Fig. 47) but in more recent years
it has been found well established in orchards, especially on
old trees, where it may become so severe as to kill them (Fig. 48).


-cj. -_
Fig. 45.-Wrong way to prune trees. Wounds of this type will be slow
in healing and thus will usually allow the entrance of wood-rotting fungi.
See Fig. 46.







Florida Agricultural Experiment Stations


On trees of bearing age the disease is confined mostly to the roots
and base of the tree trunk, but occasionally lateral roots also
are affected. Wart-like, somewhat fragile growths, often ex-
tending several inches above the surface soil and from a few
inches to a foot or more in diameter, describe fairly well the
orchard-tree characteristics of the crown gall disease. Because
of their fragility these galls are often broken off the roots and
become scattered on top of the soil when the orchard is being
cultivated.
Control.-It is important that all infected nursery stock be
destroyed, preferably by burning at the time of digging. A
few unreliable nurserymen have been known to remove galls,
paint the wounds and sell the diseased trees to their customers.
This practice is certain to disseminate the disease wherever
the trees are planted.
Where orchard trees are infected the galls should be removed
and the wounds painted with a mixture of 1 part creosote to 3
parts coal tar. This will help prevent the spread of the disease






4-j










j






Fig. 46.-In pruning make the cuts flush with the tree trunk to hasten
healing of the wound. These cuts were painted with the recommended coal
tar-creosote paint mixture. Photographed two years after cuts were made.







Insects and Diseases of the Pecan in Florida


to healthy parts of the tree. To prevent the spread to healthy
trees, infected trees should not be cultivated or harrowed.

DISEASES DUE TO NUTRITIONAL OR ENVIRONMENTAL
FACTORS

ROSETTE
Rosette (zinc deficiency) is a nutritional disease caused by
an inadequate amount of available zinc in the soil.
Prior to discovery in 1931 of the cause and control of rosette
most bearing pecan trees in the Southeast were affected. Since
then most growers have treated the soil with zinc sulfate, and
when once corrected in this way, rosette can be classed as a
minor problem, since
repeated applications
usually are not
needed.
Yellow mottling,
or chlorosis, and
crinkling of the
leaves in the tops of
trees are character-
istic of rosette in the
early stage of its de-
velopment. As the
disease progresses
the symptoms appear
on the leaves on the
lower branches. In
advanced stages the
leaves become
dwarfed, the inter-
nodes are shortened,
and gradually the
twigs and branches
in the tops of the
trees die (Fig. 49).
Often the grower ex-
periences difficulty in
detecting rosette be- Fig. 47.- Crown gall disease on nursery
cause the first symp- stock. Trees of this type should be burned to
prevent further spread of the disease. (From
toms usually are in USDA Farmers' Bul. No. 1829.)







Insects and Diseases of the Pecan in Florida


to healthy parts of the tree. To prevent the spread to healthy
trees, infected trees should not be cultivated or harrowed.

DISEASES DUE TO NUTRITIONAL OR ENVIRONMENTAL
FACTORS

ROSETTE
Rosette (zinc deficiency) is a nutritional disease caused by
an inadequate amount of available zinc in the soil.
Prior to discovery in 1931 of the cause and control of rosette
most bearing pecan trees in the Southeast were affected. Since
then most growers have treated the soil with zinc sulfate, and
when once corrected in this way, rosette can be classed as a
minor problem, since
repeated applications
usually are not
needed.
Yellow mottling,
or chlorosis, and
crinkling of the
leaves in the tops of
trees are character-
istic of rosette in the
early stage of its de-
velopment. As the
disease progresses
the symptoms appear
on the leaves on the
lower branches. In
advanced stages the
leaves become
dwarfed, the inter-
nodes are shortened,
and gradually the
twigs and branches
in the tops of the
trees die (Fig. 49).
Often the grower ex-
periences difficulty in
detecting rosette be- Fig. 47.- Crown gall disease on nursery
cause the first symp- stock. Trees of this type should be burned to
prevent further spread of the disease. (From
toms usually are in USDA Farmers' Bul. No. 1829.)







Florida Agricultural Experiment Stations


the tops of the trees and severe damage may result to the trees
before he is fully aware of its presence. Any abnormal color
of the foliage in the top of a tree should suggest the possibility
of rosette. If the leaflets of the terminal shoots near the ground
are examined carefully they frequently show yellowing between


C. -
Fig. 48.-The crown gall disease on an older tree. Note enlarged growth
at base as result of this disease.








Insects and Diseases of the Pecan in Florida


the veins which is characteristic of the disease. Severely ro-
setted trees are usually non-productive and may become so weak-
ened that they die from attacks of borers or from other causes.
However, rosette alone has never been known to kill pecan trees.
Rosette occurs under variable conditions in Florida. Eroded
or light sandy soils or those deficient in organic matter seem
to favor its development. Trees on well-drained, medium to
heavy soil types are mostly free from rosette except under un-
usual conditions, such as the addition of heavy applications of
lime to the soil to facilitate the growth of winter cover crops.
A varietal resistance or susceptibility to rosette seems to exist.


Fig. 49.-A tree seriously affected with the rosette disease. The broad-
casting over the soil of 20 pounds of zinc sulfate in two equal annual
applications was required to overcome the trouble. See Fig. 50.


'. -^








Florida Agricultural Experiment Stations


Stuart is most susceptible, while Moneymaker in most localities
usually is quite resistant.
METHODS OF CONTROL
Spraying.-Rosette may be corrected by applying zinc sulfate
in solution as a spray to the trees or by applying the dry salt
to the soil; the method of application being determined largely
by conditions confronting the grower. Soil applications are
not practical in orchards growing on neutral or alkaline soils
and under these conditions spraying is necessary. Where
growers are prepared to spray, this method is satisfactory re-
gardless of the soil condition. Three applications of spray


Fig. 50.-The same tree shown in Fig. 49 two years later, after two
annual applications of 10 pounds of zinc sulfate to the soil.







Insects and Diseases of the Pecan in Florida


solution consisting of 2 pounds of zinc sulfate, analyzing ap-
proximately 36% zinc, added to 100 gallons of water will cor-
rect rosette where the disease is present only in the mild form.
The first spray application should be made as soon after polli-
nation as possible and this should be followed by additional
applications at intervals of three to four weeks. This schedule
should be followed annually until all signs of the disease have
been eliminated; then observations should be made at regular
intervals for the first signs of its recurrence, since it is likely
to reappear at any time.
Growers can combine zinc sulfate with bordeaux mixture
(see combination insect and disease spray schedule). Four
pounds of zinc sulfate to 100 gallons of bordeaux mixture should
be used, since the lime in the bordeaux mixture somewhat re-
duces the effectiveness of the zinc. Since zinc sulfate is very
corrosive it is essential that the spray tank and pump be
thoroughly rinsed with water at the conclusion of each day's
spraying.
Soil Applications.-Since most Florida soils where pecans are
commercially grown are acid, zinc sulfate applied to the soil
will produce more satisfactory results than spray applications
because of its lasting effect. The zinc sulfate should be evenly
broadcast from near the trunk to beyond the limb spread, the
rate of application being determined to a large extent by se-
verity of the disease, nature of the soil and size of the trees.
On bearing trees not severely affected by rosette the symp-
toms usually disappear after one application of 5 pounds of
zinc sulfate per tree. Trees severely affected require more than
5 pounds, and amounts up to 10 pounds annually, over a period
of two or more years, may be required in some instances to
overcome the disease (Figs. 49 and 50).
February and March are the best months to apply the zinc
sulfate for rosette control. It may be applied later, but the
time of recovery will be delayed. If not applied until the defi-
ciency symptoms are present on the leaves little or no correction
of the disorder will be evident until the following year.
Cultivating the zinc sulfate into the soil is desirable where
practicable, as this brings about quicker results and prevents
the possibility that heavy rains will wash it away from the trees.
However, where winter cover crops are grown it is not prac-
tical to cultivate immediately if the zinc sulfate is applied in
February or March as recommended, The chemical may cause







Florida Agricultural Experiment Stations


slight burning of the winter cover crop, especially if it is not
evenly distributed, but the plants usually show no permanent
damage under good growing conditions.


Fig. 51.-Little leaf disease of pecan. Normal size leaflet at bottom.







Insects and Diseases of the Pecan in Florida


LITTLE LEAF
In the more pronounced cases of pecan little leaf the leaflets
fail to develop to normal size, the length and width being re-
duced to about %1 or 1/2 of an inch. The leaf itself is often re-
duced to a length of only one to two inches, exclusive of the
petiole or leaf stem. A slightly affected leaflet may be normal
in size, the only visible symptom of the disease being the blunt
point (Fig. 51). Some trees observed have been so severely
affected that all their leaves were composed of leaflets of the
extremely rounded and dwarfed type. On some trees the dis-
ease may be found only on certain branches, whereas other limbs
produce normal leaves and shoots. Badly affected trees do not


Fig. 52.-Thirty-five-year-old tree almost covered with Spanish moss.


A.,I







Florida Agricultural Experiment Stations


bear nuts and their growth is greatly retarded. Considerable
evidence indicates that some trees recover after one or more
years, whereas it is definitely known that the trouble has per-
sisted in others for a number of years.
This disease is of minor importance, as it seldom occurs under
orchard conditions. When found, diseased trees are usually
growing in city gardens and
lawns. It has been seen in
a number of states bordering
the Atlantic and Gulf coasts
from North Carolina to Mis-
sissippi. The cause of the
disease is not known and
consequently no remedy can
be suggested.
SPANISH MOSS
J The common gray or
Spanish moss, Tillandsia
usneoides L., occasionally
becomes noxious to pecan
trees, particularly in neg-
lected orchards, in poorly
drained locations, and espe-
cially when the trees are
growing in proximity to live
oak trees. The moss will
grow not only on trees but
also on many inanimate ob-
jects. Abundant accumula-
tions of Spanish moss have
Fig. 53.-Lichens on a pecan twig. a retarding effect upon the
vigor and growth of the tree
as a result of the shading effects produced by the masses of
moss (Fig. 52).
Control.-This moss needs sunlight for best growth, and by
inaugurating an improved cultural and fertility program the
trees are usually invigorated so that they soon keep the moss
in check. Although no spray program has been developed spe-
cifically to control it, the moss is rarely ever observed growing
on trees that have been sprayed with bordeaux mixture, ziram
or zineb.







Insects and Diseases of the Pecan in Florida


Blackmon and Sharpe" reported that spraying with the
6-2-100 bordeaux mixture during the growing season for con-
trolling pecan diseases has killed Spanish moss. They also re-
ported that arsenate of lead used at the rate of 2 pounds per
100 gallons of water proved to be a satisfactory killing agent
for Spanish moss, and as good as the low-lime bordeaux mixture.
Moss has been killed also during the dormant period by thor-
oughly wetting it with 10-2-100 bordeaux. It is necessary to
apply all materials to pecan trees with a sprayer of sufficient
power and volume to effect a satisfactory coverage. The dead
moss will hang in the trees for some time but eventually will
be blown out. If the moss is hanging in heavy, thick masses,
it may require a second application to kill all of it.

LICHENS
Lichens frequently occur on the trunks and branches of the
pecan tree. They are considered harmless but occasionally may
cause some injury to pecan trees mechanically by shading, espe-
cially in the more humid climate in the vicinity of the Gulf
Coast. Likewise, they give the tree an unsightly and unkept
appearance.
Lichens are low forms of plant life that grow in humid locali-
ties. They are not single plants but composite organisms made
up of algae which are contained in an enveloping mesh of fungus
filaments and, like mosses, obtain their food chiefly from the air.
Also like mosses, they thrive on inanimate objects such as fence
posts and rocks, as well as trunks and branches and occasionally
the foliage of some trees.
A common form is the grayish-green-paper-like growth that
occurs on the bark of pecan trees (Fig. 53). This growth may
cover areas an inch or more in diameter, or it may make an
irregular patch several inches in area. The edges are usually
free, lobed, and curl upward.
Control.-Since lichens are not considered to be injurious to
pecan trees, no spray program has been worked out for their
control. However, almost any standard fungicide, including
bordeaux mixture, lime-sulfur solutions, or organic coppers, will
readily control lichens. They are never found growing on trees
that are properly sprayed with bordeaux mixture for the con-
trol of scab and other pecan diseases.

Blackmon, G. H., and R. H. Sharpe, Pecan Growing in Florida, Bul.
437, 1951.







Florida Agricultural Experiment Stations


INJURIES DUE TO CLIMATIC CONDITIONS
WINTER INJURY
Winter injury is a disorder usually found on young, vigorous,
late-growing pecan trees or those that were defoliated in summer
and put out a new crop of leaves late in the season.
It is not always confined to young trees. Older trees, espe-
cially those that have received heavy applications of nitrogen
which tend to keep them in a vegetative condition late in the
season, may be severely injured by sudden freezes.
Winter injury is easily detected by the experienced pecan
grower. The indications are dead or dying trees in early sum-
mer, with vigorous sprouts growing up from the roots some-
what later. Close examination will show that the trunks of the
trees have been damaged near the ground. The affected tree
usually foliates and grows normally in the spring but the leaves
wither and the tree suddenly dies as soon as hot weather begins.
Shot-hole borers and other insects are sometimes present but
their damage is of a secondary nature. By cutting through the
bark into the cambium layer it is easy to detect the "sour-sap"
and discolored wood.
Control.-A young pecan orchard should be handled with ex-
treme care to prevent winter injury. Young trees should be
fertilized only in early spring and should not be cultivated later
than mid-summer, except at the time of planting winter cover
crops in the fall when the trees are approaching dormancy. This
method of handling young trees will assist in preventing vege-
tative growth late in the season and the trees will go into the
winter with the wood in a mature and hardy condition.

SUNSCALD
Injury resulting from sunscald is sometimes confused with
winter injury. The symptoms are dead or cankerous areas,
usually on the southwest side of the trees or on the tops of
larger branches. Like winter injury, sunscald occurs mostly
on young trees but also on older ones that have been cut back for
topworking to some other variety. Bright sunshine on summer
days which raises the temperature of unshaded bark to a lethal
point or on winter days which raises the bark temperature dur-
ing the daytime only, followed by a sudden and relatively severe
drop in temperature at night, is the probable cause of sunscald.
The dead areas in the bark furnish ideal entrance places for
borers and other insects and for wood-rotting fungi.







Florida Agricultural Experiment Stations


INJURIES DUE TO CLIMATIC CONDITIONS
WINTER INJURY
Winter injury is a disorder usually found on young, vigorous,
late-growing pecan trees or those that were defoliated in summer
and put out a new crop of leaves late in the season.
It is not always confined to young trees. Older trees, espe-
cially those that have received heavy applications of nitrogen
which tend to keep them in a vegetative condition late in the
season, may be severely injured by sudden freezes.
Winter injury is easily detected by the experienced pecan
grower. The indications are dead or dying trees in early sum-
mer, with vigorous sprouts growing up from the roots some-
what later. Close examination will show that the trunks of the
trees have been damaged near the ground. The affected tree
usually foliates and grows normally in the spring but the leaves
wither and the tree suddenly dies as soon as hot weather begins.
Shot-hole borers and other insects are sometimes present but
their damage is of a secondary nature. By cutting through the
bark into the cambium layer it is easy to detect the "sour-sap"
and discolored wood.
Control.-A young pecan orchard should be handled with ex-
treme care to prevent winter injury. Young trees should be
fertilized only in early spring and should not be cultivated later
than mid-summer, except at the time of planting winter cover
crops in the fall when the trees are approaching dormancy. This
method of handling young trees will assist in preventing vege-
tative growth late in the season and the trees will go into the
winter with the wood in a mature and hardy condition.

SUNSCALD
Injury resulting from sunscald is sometimes confused with
winter injury. The symptoms are dead or cankerous areas,
usually on the southwest side of the trees or on the tops of
larger branches. Like winter injury, sunscald occurs mostly
on young trees but also on older ones that have been cut back for
topworking to some other variety. Bright sunshine on summer
days which raises the temperature of unshaded bark to a lethal
point or on winter days which raises the bark temperature dur-
ing the daytime only, followed by a sudden and relatively severe
drop in temperature at night, is the probable cause of sunscald.
The dead areas in the bark furnish ideal entrance places for
borers and other insects and for wood-rotting fungi.







Florida Agricultural Experiment Stations


INJURIES DUE TO CLIMATIC CONDITIONS
WINTER INJURY
Winter injury is a disorder usually found on young, vigorous,
late-growing pecan trees or those that were defoliated in summer
and put out a new crop of leaves late in the season.
It is not always confined to young trees. Older trees, espe-
cially those that have received heavy applications of nitrogen
which tend to keep them in a vegetative condition late in the
season, may be severely injured by sudden freezes.
Winter injury is easily detected by the experienced pecan
grower. The indications are dead or dying trees in early sum-
mer, with vigorous sprouts growing up from the roots some-
what later. Close examination will show that the trunks of the
trees have been damaged near the ground. The affected tree
usually foliates and grows normally in the spring but the leaves
wither and the tree suddenly dies as soon as hot weather begins.
Shot-hole borers and other insects are sometimes present but
their damage is of a secondary nature. By cutting through the
bark into the cambium layer it is easy to detect the "sour-sap"
and discolored wood.
Control.-A young pecan orchard should be handled with ex-
treme care to prevent winter injury. Young trees should be
fertilized only in early spring and should not be cultivated later
than mid-summer, except at the time of planting winter cover
crops in the fall when the trees are approaching dormancy. This
method of handling young trees will assist in preventing vege-
tative growth late in the season and the trees will go into the
winter with the wood in a mature and hardy condition.

SUNSCALD
Injury resulting from sunscald is sometimes confused with
winter injury. The symptoms are dead or cankerous areas,
usually on the southwest side of the trees or on the tops of
larger branches. Like winter injury, sunscald occurs mostly
on young trees but also on older ones that have been cut back for
topworking to some other variety. Bright sunshine on summer
days which raises the temperature of unshaded bark to a lethal
point or on winter days which raises the bark temperature dur-
ing the daytime only, followed by a sudden and relatively severe
drop in temperature at night, is the probable cause of sunscald.
The dead areas in the bark furnish ideal entrance places for
borers and other insects and for wood-rotting fungi.







Insects and Diseases of the Pecan in Florida


Control.-One of the best methods of control is to head the
young trees as close to the ground as practicable. Do not prune
off lower limbs until the trees have advanced several growing
seasons, as the low lateral limbs increase the protective shading
of the trunk. Wrapping the trunks with gunny sacks or white-
washing them will aid in preventing sunscald.
LIGHTNING INJURY
Lightning frequently causes a type of injury to pecan trees
that is often mistaken for the effects of some parasitic disease.


Fig. 54.-Tree struck by lightning in June, with bark split on trunk to
the ground. Some branches died about four weeks later, while the remain-
der of the tree recovered slightly. Photographed August 15.







Florida Agricultural Experiment Stations


Observations indicate that there are very few orchards where
the trees have reached bearing age without at least one tree
having been struck by lightning.
When a pecan tree is struck by lightning the principal visible
injury may be confined either to the limbs and branches or to
the tree trunk (Fig. 54). The visible injury may consist of a
narrow split in the bark extending from a branch in the top
down the trunk to the ground, or the bark may be completely
peeled from the trunk, especially near the ground. If the bark
only is split the tree usually survives, but if it is peeled from
the trunk the tree dies within a few weeks. Following lightning
injury there is a yellowing of the leaves and they soon begin to
drop, resulting in partial to complete defoliation. The time
required for the defoliation is usually from 30 to 60 days after
the tree has been struck.
Observations indicate that definite signs of lightning injury
are confined to the trees that receive direct hits.
Control.-There is no practical control of lightning, but the
injuries should be treated. If the tree is killed outright it should
be removed to prevent it becoming infested by borers that later
may damage other trees in the planting. The limbs which are
killed should be pruned out and the wounds painted with the
coal tar-creosote mixture as recommended under "Wood Rot."
The grower should not act too hastily on removing injured trees.
since a large percentage of them eventually recover.

INSECTICIDES AND FUNGICIDES
PREPARATION OF BORDEAUX MIXTURE
Home-made low-lime bordeaux mixture, even after more than
30 years' investigations, is still one of the best and most eco-
nomical fungicides for the control of pecan scab and other para-
sitic leaf diseases. Furthermore, there is no better or cheaper
form of bordeaux mixture known than that made at home with
bluestone (copper sulfate), lime and water. Growers are ad-
vised to use the finely powdered or "snow" form of bluestone
and a high-calcium hydrated lime for making the bordeaux mix-
ture. Powdered bluestone or copper sulfate is in particles about
the size of granulated sugar and dissolves rapidly in water. This
"snow" form of bluestone costs slightly more than the large
crystals but the added cost is offset by the saving of time and
labor in dissolving it.







Florida Agricultural Experiment Stations


Observations indicate that there are very few orchards where
the trees have reached bearing age without at least one tree
having been struck by lightning.
When a pecan tree is struck by lightning the principal visible
injury may be confined either to the limbs and branches or to
the tree trunk (Fig. 54). The visible injury may consist of a
narrow split in the bark extending from a branch in the top
down the trunk to the ground, or the bark may be completely
peeled from the trunk, especially near the ground. If the bark
only is split the tree usually survives, but if it is peeled from
the trunk the tree dies within a few weeks. Following lightning
injury there is a yellowing of the leaves and they soon begin to
drop, resulting in partial to complete defoliation. The time
required for the defoliation is usually from 30 to 60 days after
the tree has been struck.
Observations indicate that definite signs of lightning injury
are confined to the trees that receive direct hits.
Control.-There is no practical control of lightning, but the
injuries should be treated. If the tree is killed outright it should
be removed to prevent it becoming infested by borers that later
may damage other trees in the planting. The limbs which are
killed should be pruned out and the wounds painted with the
coal tar-creosote mixture as recommended under "Wood Rot."
The grower should not act too hastily on removing injured trees.
since a large percentage of them eventually recover.

INSECTICIDES AND FUNGICIDES
PREPARATION OF BORDEAUX MIXTURE
Home-made low-lime bordeaux mixture, even after more than
30 years' investigations, is still one of the best and most eco-
nomical fungicides for the control of pecan scab and other para-
sitic leaf diseases. Furthermore, there is no better or cheaper
form of bordeaux mixture known than that made at home with
bluestone (copper sulfate), lime and water. Growers are ad-
vised to use the finely powdered or "snow" form of bluestone
and a high-calcium hydrated lime for making the bordeaux mix-
ture. Powdered bluestone or copper sulfate is in particles about
the size of granulated sugar and dissolves rapidly in water. This
"snow" form of bluestone costs slightly more than the large
crystals but the added cost is offset by the saving of time and
labor in dissolving it.








Insects and Diseases of the Pecan in Florida


Hydrated lime can be purchased in 50-pound sacks in most
towns. Although hydrated lime as ordinarily sold in the South-
east, especially that manufactured in Alabama and Tennessee,
is usually satisfactory for making bordeaux mixture, growers
nevertheless should demand that it contain at least 98 % calcium
hydroxide. The use of hydrated lime has several advantages
over quick lime. It is properly slaked when purchased, and if
stored in the bags and in a dry place it deteriorates A..%%wl; it
is relatively free from grit, and a "milk of lime" (a suspension
of 6 pounds of lime stirred into about 5 gallons of water) can
be prepared in less time than is required with quick lime.
A 6-2-100 bordeaux mixture for use in a 300-gallon spray tank
may be prepared in the following manner: Weigh out 18 pounds
of powdered (snow-form) bluestone (copper sulfate) and 6
pounds of hydrated lime.12 Add about 5 gallons of water to the
lime in a separate container to make the milk -of lime mixture.
The bluestone may be dissolved by placing it in the strainer of
the spray tank while the tank is being filled. When the tank
is about 3/ full and all the bluestone is dii-'..l\ved' the milk of
lime should be slowly added with the agitator running so as to
mix thoroughly the lime with the bluestone solution.

ZIRAM AND ZINEB "
These are new and effective fungicides containing zinc salts
of the organic carbamate compounds as the active agents. They
are compatible with insecticides such as nicotine sulfate, DDT,
parathion, and toxaphene, that are used for the control of pecan
insects. A 2-100 spray mixture for use in a 500-gallon sprayer
tank may be made by weighing 10 pounds of the material in a
container and adding sufficient water to make a paste. Then
keep adding water until it thins out, when it is poured into the
sprayer tank while it is being filled with water. It is preferable
to delay the addition of the slurry until the tank is nearly filled
with water to insure the most complete suspension possible of
the zinc salts in the water. These zinc salts are heavy and sepa-
rate from the water quickly. Therefore, the mixture must be

12 In preparing the 4-1-100 bordeaux mixture, weigh out 12 pounds of
copper sulfate and 3 pounds of hydrated lime for a 300-gallon spray tank.
1 Contains zinc dimethyl-dithiocarbamate as the active agent. Trade
names for this material are Zerlate, Karbam White, Methasan, Zimate, and
others.
Contains zinc ethylene bis-dithiocarbamate as the active agent. Trade
names for this material are Dithane Z-78 and others.







Florida Agricultural Experiment Stations


thoroughly agitated while it is being applied. One quart of
summer oil emulsion added to each 100 gallons of spray mixture
is an excellent sticker spreader.

DDT
DDT (dichloro-diphenyl-trichloroethane) is one of the new
organic insecticides. It is available for use as an insecticide
as a wettable powder containing either 50 or 75 percent DDT
and as an emulsifiable liquid containing 25% DDT by weight.
The wettable powders are generally preferred for making spray
mixtures for application to pecan trees.

PARATHION
Parathion (O,0-diethyl O-p-nitrophenyl thiophosphate) is one
of the new organic phosphorus insecticides. It is available for
use as a wettable powder containing 15% or 25% of parathion.

SUMMER OIL EMULSIONS
The summer oil emulsions are chemically inert and are not
likely to injure the foliage or nuts, when used as a spreader-
sticker with bordeaux mixture or any of the new organic fungi-
cides and insecticides that are recommended for use on pecans
as wettable powders.
NICOTINE
Nicotine is an extract obtained from the stems and leaves of
tobacco, mostly from the waste products in cigar and cigarette
manufacture. It is usually sold as nicotine sulfate, containing
40 percent of actual nicotine. The nicotine sulfate is not rapidly
volatile and is employed chie-y in the preparation of orchard
sprays. Nicotine sulfate was formerly used extensively for
aphid control but in this bulletin it is recommended only in
phylloxera control.
LIME-SULFUR
The concentrated commercial liquid lime-sulfur usually tests
about 330 on the Baume hydrometer. This material should al-
ways be diluted. Lime-sulfur should never be used with soap
or with soap-oil emulsions without stabilizers.

COMBINED SPRAYS FOR INSECTS AND DISEASE CONTROL
When desirable it is possible to combine in one mixture and
application the spray materials recommended for the control of
insects and diseases, thus saving the time and labor required to







Florida Agricultural Experiment Stations


thoroughly agitated while it is being applied. One quart of
summer oil emulsion added to each 100 gallons of spray mixture
is an excellent sticker spreader.

DDT
DDT (dichloro-diphenyl-trichloroethane) is one of the new
organic insecticides. It is available for use as an insecticide
as a wettable powder containing either 50 or 75 percent DDT
and as an emulsifiable liquid containing 25% DDT by weight.
The wettable powders are generally preferred for making spray
mixtures for application to pecan trees.

PARATHION
Parathion (O,0-diethyl O-p-nitrophenyl thiophosphate) is one
of the new organic phosphorus insecticides. It is available for
use as a wettable powder containing 15% or 25% of parathion.

SUMMER OIL EMULSIONS
The summer oil emulsions are chemically inert and are not
likely to injure the foliage or nuts, when used as a spreader-
sticker with bordeaux mixture or any of the new organic fungi-
cides and insecticides that are recommended for use on pecans
as wettable powders.
NICOTINE
Nicotine is an extract obtained from the stems and leaves of
tobacco, mostly from the waste products in cigar and cigarette
manufacture. It is usually sold as nicotine sulfate, containing
40 percent of actual nicotine. The nicotine sulfate is not rapidly
volatile and is employed chie-y in the preparation of orchard
sprays. Nicotine sulfate was formerly used extensively for
aphid control but in this bulletin it is recommended only in
phylloxera control.
LIME-SULFUR
The concentrated commercial liquid lime-sulfur usually tests
about 330 on the Baume hydrometer. This material should al-
ways be diluted. Lime-sulfur should never be used with soap
or with soap-oil emulsions without stabilizers.

COMBINED SPRAYS FOR INSECTS AND DISEASE CONTROL
When desirable it is possible to combine in one mixture and
application the spray materials recommended for the control of
insects and diseases, thus saving the time and labor required to







Florida Agricultural Experiment Stations


thoroughly agitated while it is being applied. One quart of
summer oil emulsion added to each 100 gallons of spray mixture
is an excellent sticker spreader.

DDT
DDT (dichloro-diphenyl-trichloroethane) is one of the new
organic insecticides. It is available for use as an insecticide
as a wettable powder containing either 50 or 75 percent DDT
and as an emulsifiable liquid containing 25% DDT by weight.
The wettable powders are generally preferred for making spray
mixtures for application to pecan trees.

PARATHION
Parathion (O,0-diethyl O-p-nitrophenyl thiophosphate) is one
of the new organic phosphorus insecticides. It is available for
use as a wettable powder containing 15% or 25% of parathion.

SUMMER OIL EMULSIONS
The summer oil emulsions are chemically inert and are not
likely to injure the foliage or nuts, when used as a spreader-
sticker with bordeaux mixture or any of the new organic fungi-
cides and insecticides that are recommended for use on pecans
as wettable powders.
NICOTINE
Nicotine is an extract obtained from the stems and leaves of
tobacco, mostly from the waste products in cigar and cigarette
manufacture. It is usually sold as nicotine sulfate, containing
40 percent of actual nicotine. The nicotine sulfate is not rapidly
volatile and is employed chie-y in the preparation of orchard
sprays. Nicotine sulfate was formerly used extensively for
aphid control but in this bulletin it is recommended only in
phylloxera control.
LIME-SULFUR
The concentrated commercial liquid lime-sulfur usually tests
about 330 on the Baume hydrometer. This material should al-
ways be diluted. Lime-sulfur should never be used with soap
or with soap-oil emulsions without stabilizers.

COMBINED SPRAYS FOR INSECTS AND DISEASE CONTROL
When desirable it is possible to combine in one mixture and
application the spray materials recommended for the control of
insects and diseases, thus saving the time and labor required to







Florida Agricultural Experiment Stations


thoroughly agitated while it is being applied. One quart of
summer oil emulsion added to each 100 gallons of spray mixture
is an excellent sticker spreader.

DDT
DDT (dichloro-diphenyl-trichloroethane) is one of the new
organic insecticides. It is available for use as an insecticide
as a wettable powder containing either 50 or 75 percent DDT
and as an emulsifiable liquid containing 25% DDT by weight.
The wettable powders are generally preferred for making spray
mixtures for application to pecan trees.

PARATHION
Parathion (O,0-diethyl O-p-nitrophenyl thiophosphate) is one
of the new organic phosphorus insecticides. It is available for
use as a wettable powder containing 15% or 25% of parathion.

SUMMER OIL EMULSIONS
The summer oil emulsions are chemically inert and are not
likely to injure the foliage or nuts, when used as a spreader-
sticker with bordeaux mixture or any of the new organic fungi-
cides and insecticides that are recommended for use on pecans
as wettable powders.
NICOTINE
Nicotine is an extract obtained from the stems and leaves of
tobacco, mostly from the waste products in cigar and cigarette
manufacture. It is usually sold as nicotine sulfate, containing
40 percent of actual nicotine. The nicotine sulfate is not rapidly
volatile and is employed chie-y in the preparation of orchard
sprays. Nicotine sulfate was formerly used extensively for
aphid control but in this bulletin it is recommended only in
phylloxera control.
LIME-SULFUR
The concentrated commercial liquid lime-sulfur usually tests
about 330 on the Baume hydrometer. This material should al-
ways be diluted. Lime-sulfur should never be used with soap
or with soap-oil emulsions without stabilizers.

COMBINED SPRAYS FOR INSECTS AND DISEASE CONTROL
When desirable it is possible to combine in one mixture and
application the spray materials recommended for the control of
insects and diseases, thus saving the time and labor required to







Florida Agricultural Experiment Stations


thoroughly agitated while it is being applied. One quart of
summer oil emulsion added to each 100 gallons of spray mixture
is an excellent sticker spreader.

DDT
DDT (dichloro-diphenyl-trichloroethane) is one of the new
organic insecticides. It is available for use as an insecticide
as a wettable powder containing either 50 or 75 percent DDT
and as an emulsifiable liquid containing 25% DDT by weight.
The wettable powders are generally preferred for making spray
mixtures for application to pecan trees.

PARATHION
Parathion (O,0-diethyl O-p-nitrophenyl thiophosphate) is one
of the new organic phosphorus insecticides. It is available for
use as a wettable powder containing 15% or 25% of parathion.

SUMMER OIL EMULSIONS
The summer oil emulsions are chemically inert and are not
likely to injure the foliage or nuts, when used as a spreader-
sticker with bordeaux mixture or any of the new organic fungi-
cides and insecticides that are recommended for use on pecans
as wettable powders.
NICOTINE
Nicotine is an extract obtained from the stems and leaves of
tobacco, mostly from the waste products in cigar and cigarette
manufacture. It is usually sold as nicotine sulfate, containing
40 percent of actual nicotine. The nicotine sulfate is not rapidly
volatile and is employed chie-y in the preparation of orchard
sprays. Nicotine sulfate was formerly used extensively for
aphid control but in this bulletin it is recommended only in
phylloxera control.
LIME-SULFUR
The concentrated commercial liquid lime-sulfur usually tests
about 330 on the Baume hydrometer. This material should al-
ways be diluted. Lime-sulfur should never be used with soap
or with soap-oil emulsions without stabilizers.

COMBINED SPRAYS FOR INSECTS AND DISEASE CONTROL
When desirable it is possible to combine in one mixture and
application the spray materials recommended for the control of
insects and diseases, thus saving the time and labor required to







Insects and Diseases of the Pecan in Florida


make separate applications. The spray schedule for combating
pecan insects and diseases, if carefully followed, will give com-
mercial control of most of the important insects and diseases
that are present in Florida. However, a general spray schedule
is not always the most satisfactory one for a particular orchard
and the details of the control program should be worked out to
meet local conditions.
CONCENTRATE SPRAYING
Concentrate sprayers have not had a thorough trial for con-
trol of insects and diseases of pecans in the southeastern United
States. Although certain insects of pecans have been controlled
satisfactorily with concentrate sprayers, preliminary investiga-
tions indicate that this method of applying fungicides gave less
scab control than when applied with the hydraulic sprayer.
Where speed is a factor, and if the orchard warrants more than
one spray machine, alternating the hydraulic and concentrate
applications may result in commercial control of pecan scab.
Because pecan scab is difficult to control under conditions
favorable for its development, even with hydraulic sprayers, it
is considered that concentrate sprayers for pecan disease con-
trol are still in the experimental stage and further work is
needed before this method can be recommended for scab control.

THE HYDRAULIC SPRAY OUTFIT
What may be termed medium-sized portable spray outfits have
been extensively used for spraying pecan trees. Such machines
may be equipped with motors capable of developing from 15 to
25 horsepower or they may be driven by power take-offs on
tractors or trucks. Tanks should hold at least 300 gallons of
spray material. The machine should have a pump capacity
ranging from 25 to 35 gallons per minute and be capable of main-
taining a pressure of 400 to 600 pounds with the spray gun
open. Machines of this type, under average conditions, will
spray trees from 40 to 60 feet in height. Since the operator
should stand on top of the machine, a spray gun that can be
adjusted to produce both a wide-angled mist and a narrow,
driving spray, with a short hose, 8 to 10 feet long and 3/4, inch
in inside diameter, is preferable.
If the grower has a small orchard of young trees he could
purchase a smaller machine than the one recommended above.
If at all possible he should purchase the machine from a dealer
who carries in stock a supply of parts and equipment.







Insects and Diseases of the Pecan in Florida


make separate applications. The spray schedule for combating
pecan insects and diseases, if carefully followed, will give com-
mercial control of most of the important insects and diseases
that are present in Florida. However, a general spray schedule
is not always the most satisfactory one for a particular orchard
and the details of the control program should be worked out to
meet local conditions.
CONCENTRATE SPRAYING
Concentrate sprayers have not had a thorough trial for con-
trol of insects and diseases of pecans in the southeastern United
States. Although certain insects of pecans have been controlled
satisfactorily with concentrate sprayers, preliminary investiga-
tions indicate that this method of applying fungicides gave less
scab control than when applied with the hydraulic sprayer.
Where speed is a factor, and if the orchard warrants more than
one spray machine, alternating the hydraulic and concentrate
applications may result in commercial control of pecan scab.
Because pecan scab is difficult to control under conditions
favorable for its development, even with hydraulic sprayers, it
is considered that concentrate sprayers for pecan disease con-
trol are still in the experimental stage and further work is
needed before this method can be recommended for scab control.

THE HYDRAULIC SPRAY OUTFIT
What may be termed medium-sized portable spray outfits have
been extensively used for spraying pecan trees. Such machines
may be equipped with motors capable of developing from 15 to
25 horsepower or they may be driven by power take-offs on
tractors or trucks. Tanks should hold at least 300 gallons of
spray material. The machine should have a pump capacity
ranging from 25 to 35 gallons per minute and be capable of main-
taining a pressure of 400 to 600 pounds with the spray gun
open. Machines of this type, under average conditions, will
spray trees from 40 to 60 feet in height. Since the operator
should stand on top of the machine, a spray gun that can be
adjusted to produce both a wide-angled mist and a narrow,
driving spray, with a short hose, 8 to 10 feet long and 3/4, inch
in inside diameter, is preferable.
If the grower has a small orchard of young trees he could
purchase a smaller machine than the one recommended above.
If at all possible he should purchase the machine from a dealer
who carries in stock a supply of parts and equipment.







Florida Agricultural Experiment Stations


Availability of water is as important as selection of the ma-
chine. It should be centrally located and, if a well is used, an
elevated water tank holding several thousand gallons should be
provided. A 4-inch outlet should be placed in this tank which
will allow the filling of a 300-gallon spray tank in three to five
minutes. If equipment and labor are available a supply tank
that will carry water directly to the spray machine will save
much time. With equipment of this type under ordinary condi-
tions an operator should be able to apply 4,000 gallons of spray
per day. Such equipment should be adequate for an orchard of
1,500 to 2,000 trees, ranging in height from 40 to 60 feet.

APPLYING THE SPRAY MATERIAL
In applying all sprays it is essential that all leaves and nuts
be evenly covered with a thin film. Tops of trees, as well as
lower branches, must be sprayed. Do not drench or overspray,
as this wastes material and does no good and may result in
injury. Best results are obtained when the spray uniformly
wets all leaves and nuts, with little or no runoff of the material .

WARNING ON USE AND STORAGE OF POISONS
Many insecticides listed in this bulletin are poisonous to hu-
mans and to animals and should be handled with care. All
poisons should be kept properly labeled and should be stored
where they will not be mistaken for food or medicine, and where
children and others unaware of their danger cannot have access
to them.
DDT is poisonous to man and animals but can be handled
safely as recommended for pecan insects. When preparing
spray mixtures, avoid breathing the dry material, keep hands
away from mouth and wash before handling food.
Note.-If a leaf scorch condition caused by mites appears on
DDT-sprayed trees, apply a miticide as recommended for mite
control.
Parathion is an extremely poisonous material. It is very
effective against pecan insects but it is also highly toxic to man
and livestock. The material should not be inhaled or allowed
to come in contact with the skin. Do not smoke, and keep hands
away from mouth and wash before handling food. All precau-
tions printed on the containers should be strictly observed.
Nicotine is a very poisonous material. Some persons are very







Florida Agricultural Experiment Stations


Availability of water is as important as selection of the ma-
chine. It should be centrally located and, if a well is used, an
elevated water tank holding several thousand gallons should be
provided. A 4-inch outlet should be placed in this tank which
will allow the filling of a 300-gallon spray tank in three to five
minutes. If equipment and labor are available a supply tank
that will carry water directly to the spray machine will save
much time. With equipment of this type under ordinary condi-
tions an operator should be able to apply 4,000 gallons of spray
per day. Such equipment should be adequate for an orchard of
1,500 to 2,000 trees, ranging in height from 40 to 60 feet.

APPLYING THE SPRAY MATERIAL
In applying all sprays it is essential that all leaves and nuts
be evenly covered with a thin film. Tops of trees, as well as
lower branches, must be sprayed. Do not drench or overspray,
as this wastes material and does no good and may result in
injury. Best results are obtained when the spray uniformly
wets all leaves and nuts, with little or no runoff of the material .

WARNING ON USE AND STORAGE OF POISONS
Many insecticides listed in this bulletin are poisonous to hu-
mans and to animals and should be handled with care. All
poisons should be kept properly labeled and should be stored
where they will not be mistaken for food or medicine, and where
children and others unaware of their danger cannot have access
to them.
DDT is poisonous to man and animals but can be handled
safely as recommended for pecan insects. When preparing
spray mixtures, avoid breathing the dry material, keep hands
away from mouth and wash before handling food.
Note.-If a leaf scorch condition caused by mites appears on
DDT-sprayed trees, apply a miticide as recommended for mite
control.
Parathion is an extremely poisonous material. It is very
effective against pecan insects but it is also highly toxic to man
and livestock. The material should not be inhaled or allowed
to come in contact with the skin. Do not smoke, and keep hands
away from mouth and wash before handling food. All precau-
tions printed on the containers should be strictly observed.
Nicotine is a very poisonous material. Some persons are very







Insects and Diseases of the Pecan in Florida 75

susceptible to its effects and may develop acute nausea, while
others can handle it freely without suffering any noticeable ef-
fects. Illness can be caused also by the absorption of nicotine
through the skin, and operators should not wear clothing that
is wet with spray solution containing nicotine.
Lime-sulfur is very caustic to the skin, when used in high
concentrations. Persons exposed to this material should pro-
tect their faces by covering them with grease or petroleum jelly
before they begin spraying, and should avoid getting the mate-
rial in the eyes, as this would cause temporary discomfort. The
hands may be protected by wearing oiled leather gloves.








SPRAY PROGRAM FOR CONTROL OF PECAN INSECTS AND DISEASES


Number and Time of
Spray Applications


For Control Of:


First application when first
leaves are half grown

Second application about the
time the tips of the small
nuts have turned brown









Third application three
weeks after second



Fourth application three
weeks after third


Scab, downy spot, nurs-
ery blight

Scab, nursery blight,
brown leaf spot, pecan
nut casebearer, aphids









Scab, nursery blight,
powdery mildew, blotch,
brown leaf spot, rosette


Scab, nursery blight,
powdery mildew, pecan
leaf casebearer, aphids,
mites


4-1-100 bordeaux mixture

6-2-100 bordeau mixture
+ 2 lbs. of 50% wettable
DDT or 4-
2 lbs. 15% wettable para-
thion or
2 lbs. ziram (76%) in 100
gal. + 1 qt. summer oil
emulsion + 2 lbs. of 50%
wettable DDT
or +
2 lbs. 15% wettable para-
thion

6-2-100 bordeaux mixture
or
2 lbs. ziram (76%) in 100
gal. + 1 qt. summer oil
emulsion

6-2-100 bordeaux mixture
+ 2 lbs. 15% wettable
parathion
or
2 lbs. ziram (76%) in 100
gal. + 1 qt. summer oil
emulsion + 2 lbs. 15%
wettable parathion


To protect the foliage

A fungicide is necessary to
protect the nuts and foliage.
Add 4 lbs. zinc sulfate if ro-
sette is present. Insecticide
is important to control nut
casebearer. Addition of sum-
mer oil to ziram improves its
fungicidal action. Use para-
thion if aphids are present.
See caution note on use of
parathion on page 74.

Add 4 lbs. zinc sulfate if ro-
sette is present



Add 4 lbs. zinc sulfate if ro-
sette is present. See caution
note on use of parathion


Fifth application last week
in July or early in August


Scab 6-2-100 bordeaux mixture
+ 2 lbs. 15% wettable
parathion
or
2 lbs. ziram (76%) in 100
gal. + 1 (t. summer oil
emulsion + 2 lbs. 15%
wettable parathion


When the rainy season ex-
tends through July, this ap-
plication is necessary. Use
parathion if aphids are
present.


Materials


Remarks