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Pecan disease and insect control suggestions

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Title:
Pecan disease and insect control suggestions
Creator:
Large, John R.
Publisher:
Big Bend Horticultural Laboratory, University of Florida

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University of Florida
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All applicable rights reserved by the source institution and holding location.
Resource Identifier:
145566001 ( OCLC )

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/'O4


BIG BEND HORTICULTURAL LABORATORY
Monticello, Florida

Big Bend Hort. Lab. Mimeo Report-BBD-67-4 March 1, 1967
tt- .' '*j p ",

PECAN D SEASE AND I SECT CONTROL SUGGESTIONS2

John R. Large, Job Van Duyn and H. W. Young1
A.S. -Univ. of Florida
A large number of diseasesE aiinsects attack the leaves, shoots and nuts of
the pecan tree during the long growing season.

Spraying for control of diseases and insects is a very important factor in
the production of pecans. A good crop of nuts may be totally lost if not protected
from pests. In addition to protecting maturing nuts, spraying contributes to the
production of a crop the next year by preventing defoliation.

Diseases spread most rapidly early in the growing season and during periods
of high humidity. Some insects such as nut casebearer, weevil and shuckworm occur
in orchards at particular times, whereas, others may become a problem at any time.
The timing of spray applications is very important and each grower should learn
to recognize insect and disease problems to determine the best time to spray.

In applying spray materials all leaves, twigs and nuts should be covered.
It is important that adequate machinery be used and the operator be well trained
in its use. Poor coverage during any part of the growing season may lead to severe
disease or insect damage.

Spray may be applied by hydraulic ground sprayer, concentrate air blast
sprayer, airplane or helicopter. Some modern sprayers, known as concentrate spray- ,
ers, use less water to carry chemicals than conventional hydraulic equipment.
Both concentrate and dilute sprays are expressed as the amount of pesticide form-
ulation per 100 gallons of water. The same amount of chemical is sprayed on each
tree with either the dilute or concentrate sprayers. Table III gives the gallons
of spray per tree for each type of equipment.

The following spray schedule (Table I) carefully followed will give commercial
control of important disease and insect pests. However, a general spray schedule
is not always the most satisfactory for a particular orchard.

Zineb and Bordeaux mixture are effective against scab, powdery mildew and
other fungus diseases, but Cyprex or Du-Ter are more effective against scab.
Cyprex and Du-Ter will not control powdery mildew and sulfur or Karathane must be
added to control this disease. Cyprex should not be used on Moore and Van Deman
varieties. April applications of Cyprex on these varieties caused marginal burning
and defoliation of the young leaves. Zineb plus Oil, 2 lbs. + 1 qt./100, in April
followed by Cyprex can be used on Moore and Van Deman with only slight injury.


1Associate Plant Pathologist, Research Associate in Entomology and Associate
Horticulturist and Head.

2Prepared in cooperation with J. E. Brogdon, Extension Entomologist and
R. S. Mullin, Extension Plant Pathologist, University of Florida, Gainesville.












Where rosette is present use a spray bf neutral zinc (2 lbs.) or zinc sulfate
(2 lbs. of 65%). Zinc sulfate is very corrosive and will rust out machinery. It
must be washed out with soap and water after use.

On scab resistant varieties such as Desirable, Curtis, Elliott, Farley and
usually Stuart the total number of sprays may be fewer than on scab susceptible
varieties. Prepollination sprays and those to control nut casebearer and shuck-
worm should not be omitted. In dry weather, if scab is not serious, one or more
of the summer applications of Du-Ter may be omitted.

For dooryard trees or in orchards where cattle are grazed, Malathion should
be used instead of Parathion. Malathion may not adequately control shuckworm and
either EPN or Guthion should be used in commercial orchards (See precautions).
For dooryard trees, Malathion is recommended for all insect sprays.

PRECAUTIONS

Parathion, EPN and Guthion are especially toxic and should be applied only by
properly trained and equipped operators. Read the entire label before opening
any pesticide container and heed all cautions and warnings. Store pesticides in
original labeled containers out of reach of children, pets and livestock, and
preferably under lock and key. Dispose of left over spray materials and all empty
containers promptly and safely. Follow the recommended dosage and waiting periods
to avoid excess residues and injury to plants and animals. Avoid drift of pesti-
cides to adjacent areas. See, Table II on Residue Tolerances.









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TABLE II. RESIDUE TOLERANCES AND LIMITATIONS FOR CHEMICALS RECOMMENDED FOR
PECANS IN THIS PUBLICATION.

CHEMICAL RESIDUE TOLERANCE INTERVAL BETWEEN LAST APPLICATION AND
(PPM) HARVEST AND OTHER RESTRICTIONS.


EPN 0.5


Guthion


Do not apply within 21 days of harvest.


Do not apply after shuck split. Do not
graze livestock in treated orchards within
21 days after treatment.


Malathion 8.0 No time limitations.


Parathion --- Do not apply within 15 days of harvest
or after shuck open.


Bordeaux Mixture Exempt No time limitations.


Du-Ter


not
not


apply after shucks start to open.
graze livestock in treated orchards.


Cyprex --- Do not apply after shucks start to open.
Do not graze meat or dairy animals in
treated orchards.


Zineb --- Do not apply within 45 days of harvest.


Sulfur Safe No time limitations.


Thiodan --- Do not apply after shuck-split. Do not
graze meat or dairy animals in treated
orchards.


-[I










-7-


TABLE III.


GALLONS OF SPRAY BY TREE SIZE.


TYPE OF EQUIPMENT


GALLONS OF SPRAY BY TREE SIZE


Small
(Under 25 feet)


Medium
(25 35 feet)


Large
(Over 35 feet)


4 10


AIR BLAST


HYDRAULIC


MIST BLOWER


AIRPLANE


1 1/2


5 15


7 1/2 30


30


2 1/2


FROM: Harris, E. D. and N. E. McGlohon. 1967
Pecan Insects and Diseases and Their ContrOl.
Ga. Ag. Ext. Service, Bulletin 644.


300 cc




Full Text

PAGE 1

BIG BEND HORTICULTURAL LABORATORY Monticello, Florida Big Bend Hort. La.,Mie dpV-BD6March 1, 1967 PECAN. D SEASE AND I SECT CONTROL SUGGESTIONS2 John R. Large,, Job, Van Duyn and H. W. Young1 A..Univ. of Florida large number of d seases an sects attack the leaves, shoots and nuts of the pecan tree during the long growing season. Spraying for control of diseases and insects is a very important factor in the production of pecans. A good crop of nuts may be totally lost if not protected from pests. In addition to protecting maturing nuts, spraying contributes to the production of a crop the next year by preventing defoliation. Diseases spread most rapidly early in the growing season and during periods of high humidity. Some insects such as nut casebearer, weevil and shuckworm occur in orchards at particular times, whereas, others may become a problem at any time. The timing of spray applications is very important and each grower should learn to recognize insect and disease problems to determine the best time to spray. In applying spray materials all leaves, twigs and nuts should be covered. it is important that adequate machinery be used and the operator be well trained in its use. Poor coverage during any part of the growing season may lead to severe disease or insect damage. Spray may be applied by hydraulic ground sprayer, concentrate air blast sprayer, airplane or helicopter. Some modern sprayers, known as concentrate spray-rL:' ers, use less water to carry chemicals than conventional hydraulic equipment. Both concentrate and dilute sprays are expressed as the amount of pesticide formulation per 100 gallons of water. The same amount of chemical is sprayed on each tree with either the dilute or concentrate sprayers. Table III gives the gallons of spray per tree for each type of equipment. The following spray schedule (Table I) carefully followed will give commercial control of important disease and insect pests. However, a general spray schedule is not always the most satisfactory for a particular orchard. Zineb and Bordeaux mixture are effective against scab, powdery mildew and other fungus diseases, but Cyprex or Du-Ter are more effective against scab. Cyprex and Du-Ter will not control powdery mildew and sulfur or Karathane must be added to control this disease. Cyprex should not be used on Moore and Van Deman varieties. April applications of Cyprex on these varieties caused marginal burning and defoliation of the young leaves. Zineb plus Oil, 2 lbs. + 1 qt./lO0, in April followed by Cyprex can be used on Moore and Van Deman with only slight injury. lAssociate Plant Pathologist, Research Associate in Entomology and Associate Horticulturist and Head. 2Prepared in cooperation with J. E. Brogdon, Extension Entomologist and R. S. Mullin, Extension Plant Pathologist, University of Florida, Gainesville.

PAGE 2

-2Where rosette is present use a spk'ay of neutral zinc (2 lbs.) or zinc sulfate (2 lbs. of 65%). Zinc sulfate is very corrosive and will rust out machinery. It must be washed out with soap and water after use. On scab resistant varieties such as Desirable, Curtis, Elliott, Farley and usually Stuart the total number of sprays may be fewer than on scab susceptible varieties. Prepollination sprays and those to control nut casebearer and shuckworm should not be omitted. In dry weather, if scab is not serious, one or more of the summer applications of Du-Ter may be omitted. For dooryard trees or in orchards where cattle are grazed, Malathion should be used instead of Parathion. Malathion may not adequately control shuckworm, and either EPN or Guthion should be used in commercial orchards (See precautions). For dooryard trees, Malathion is recommended for all insect sprays. PRECAUTI ONS Parathion, EPN and Guthion are especially toxic and should be applied only by properly trained and equipped operators. Read the entire label before opening any pesticide container and heed all cautions and warnings. Store pesticides in original labeled containers out of reach of children, pets and livestock, and preferably under lock and key. Dispose of left over spray materials and all empty containers promptly and safely. Follow the recommended dosage and waiting periods to avoid excess residues and injury to plants and animals. Avoid drift of pesticides to adjacent areas. Seek Table II on Residue Tolerances.

PAGE 3

-3TABLE 1. PECAN SPRAY SCHEDULE. SPRAY PEST TO SPRAY MATERIAL(') TIME OF APPLICATION CONTROL AMOUNT PER 100 GALLONS REMARKS 1st PRE POLLINATION Scab Du-Ter 1/2 lb. (50% W/P) Bo)rdeaux mixture (6-2-100) or Zineb (65% W/P) SPRAY: When leaves or may be substituted for Du-Ter or Cyprex. Do first show green. Cyprex 1 lb. (65% W/P.) not use Cyprex on Moore and Van Deman varieties. If a spray program was not followed last year add an insecticide to control over;-wintering l af and nut casebearer. See 1st. Cover Spray. 2nd PRE POLLINATION Scab Du-Ter 1/2 lb. (50% W/P) Early sprays prevent scab from becoming estabSPRAY: When leaves Downy Spot or lished on rapidly growing foliage. See remarks are half grown. Cyprex 1 lb. (65% W/P) oai fungicides -1st. Pre-pollination Spray. 1st. COVER SPRAY: Scab Du-Ter 1/2 lb. (50% W/P) When nuts are Other or about 1/4"1 long, foliage Cyprex 1 lb. (65% W/P) This insecticide application is very important, diseases plus be sure coverage is complete. If nut caseNut CaseParathion 2 lbs. (15% W/P) bearer population is heavy, make a second app.; bearer or lication of insecticide one week later. Aphids Malathion 3 lbs. (25% W/P) See remarks on fungicides -1st. Pre-polliMites or nation Spray. EPN 2 lbs. (25% WIP) or Guthion 2 lbs. (25% W/P) or Thiodan 2 lbs. (50% W/P) (lEquivalent amounts of emulsifiable concentrate formulations of insecticides may be used. Do not use Du-Ter with emulsifiable concentrate formulations.

PAGE 4

TABLE 1. Continued: SPRAY PEST TO SPRAY MATERIAL~l) TIME OF APPLICATION CONTROL AMOUNT PER 100 GALLONS REMARKS 2nd COVER SPRAY: Scab Du-Ter 1/2 lb. (50% W/?) Sulfur (2 lbs.) is added to Du-Ter or Cyprex Three weeks after Powdery or for powdery mildew control. If sulfur does first cover spray mildew Cyprex 1 lb. (65% W/?) not control powdery mildew, use Bordeaux Other (6-2-100). If aphids or mites are a problem, foliage use parathion or malathion. diseases 3rd COVER SPRAY: Scab Du-Ter 1/2 lb. (50% WI?) If brown spot is serious use Du-Ter. If Three weeks after Powdery or aphids or mites are a problem, use parathion second cover spray. mildew Cyprex 1 lb. (65% WI?) or malathion. Other foliage diseases 4th COVER SPRAY: Scab Du-Ter 1/2 lb. (50% WI?) If aphids or mites are a problem, use Powdery or Parathion or Malathion. mildew Cyprex 1 lb. (65% WI?) Other foliage diseases (1)Equivaient amounts of emulsifiable concentrate formulations of insecticide may be used. Do not use Du-Ter with emulsifiable concentrate formulations.

PAGE 5

-5TABLE I. Continued: SPRAY PEST TO SPRAY MATERIAL~l) TIME OF APPLICATION CONTROL AMOUNT PER 100 GALLONS REMARKS" 5th COVER SPRAY: Scab Du-Ter 1/2 lb. (50% W/P) AMply 2nd and 3rd shuckworm sprays at When shell of nut Powdery or 2 week intervals. begins to harden, mildew Cyprex 1 lb. (65% W/P) about August 10. Other plus foliage EPN 1 1/2 lbs. (25% W/P) diseases or Shuckworm Guthion 2 lbs. (25% W/P) Aphids Mites (l) Equivalenlt amounts of emulsifiable concentrate formulations of insecticide may be used. Do not use Du-Ter with emulsifiable concentrate formulations.

PAGE 6

-6TABLE II.* RESIDUE TOLERANCES AND LIMITATIONS FOR CHEMICALS RECOMMENDED FOR PECANS IN THIS PUBLICATION. CHEMICAL RESIDUE TOLERANCE INTERVAL BETWEEN LAST APPLICATION AND (PPM) HARVEST AND OTHER RESTRICTIONS. EPN 0.5 Do not apply within 21 days of harvest. Guthion ---Do not apply after shuck split. Do not graze livestock in treated orchards within 21 days after treatment. Malathion 8.0 No time limitations. Parathion ---Do not apply within 15 days of harvest or after shuck open. Bordeaux Mixture Exempt No time limitations. Du-Ter ---Do not apply after shucks start to open. Do not graze livestock in treated orchards. Cyprex ---Do not apply after shucks start to open. Do not graze meat or dairy animals in treated orchards. Zineb ---Do not apply within 45 days of harvest. Sulfur Safe No time limitations. Thiodan ---Do not apply after shuck-split. Do not graze meat or dairy animals in treated orchards.

PAGE 7

TABLE III. GALLONS OF SPRAY BY TREt SIZE. TYPE OF EQUIPMENT GALLONS OF SPRAY BY TREE SIZE Small Medium Large (Under 25 feet) (25 -35 feet) (Over 35 feet) AIR BLAST 4 -10 5 -1 is71/2 -30 HYDRAULIC 15 20 30 MIST BLOWER 3 4 5 AIRPLANE 1 1/2 2 2 1/2 FROM: Harris, E. D. and N. E. McGlohon. 1967 Pecan Insects and Diseases and Their Contr~l. Ga. Ag. Ext. Service, Bulletin 644. 300 cc