Title: Pecan Insect and disease recommendations
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 Material Information
Title: Pecan Insect and disease recommendations
Physical Description: Book
Creator: Fluker, Sam S.
Publisher: Big Bend Horticultural Laboratory, University of Florida
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Bibliographic ID: UF00076520
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BIG BEND HORTICULTURAL LABORATORY
Monticello, Florida


Big Bend Hort. Lab. Mimeo Report BBL 71-2 November 19, 1970

HUME LIBRARY
PECAN INSECT AND DISEASE RECOMMENDATIONS HUME L

S. S. Fluker and W. J. Frenchl VAR i7 1371


Diseases and insects are often the limiting factors jL$.^h. pt Pcjctp4Fyda
of pecans in Florida. The nut requires about 7 months to evpelop and during
that time is subject to attack by a variety of pests. A good disease and
insect control program is important, not only in protecting the maturing crop
but it is essential to the production of high yields year after year. Trees
which are prematurely defoliated by insects, mites, and diseases frequently
set a light crop the following year. Although today's pecan grower is fortunate
to have effective fungicides, insecticides, and improved spray equipment avail-
able to him, spraying for pest control is not an easy job. It requires attention
to many details that on the surface may seem unimportant. Perhaps the three most
important factors in a spray program are timing, coverage, and rate.

Timing Pecan diseases, such as scab, must be prevented by providing a
protective covering of fungicide over all susceptible tissue from the time the
first leaves unfold until the nut is developed. If the disease becomes estab-
lished on young foliage it is more difficult to prevent infection on the nuts
during the remainder of the season. Some insects such as nut casebearer, pecan
weevil, and hickory shuckworm occur in orchards at particular and somewhat pre-
dictable times. Timing of sprays for control of these insects is very important
and each grower should learn to recognize the vulnerable stages of these insects
and time his sprays accordingly. Excessive use of insecticides should be avoid-
ed as it may create insect problems that otherwise would not exist, as well as
adding to the pollution of our environment.

Coverage In applying spray materials, all leaves, twigs, and nuts
should be covered. Hydraulic machines are designed to use large volumes of
water to carry the chemicals to the trees. Sprays should be applied until
water runs off leaves in the upper portion of the tree. Do not attempt to con-
centrate or use low volume sprays with hydraulic equipment (Table IV). Air
blast and mist blowers are designed for low volume applications. Air blast
equipment should be adjusted before the spray season begins to deliver the de-
sired volume of spray in the proper pattern as is dictated by tree size. Con-
sult instruction manuals or spray machine representative for advice on correct
placement of spray nozzles. Remember, when spraying with air blast sprayers,
the pesticide is carried to the tree in a small volume of water which is diluted
by a larger volume of air. Too fast a rate of travel will result in insuffi-
cient coverage where the trees are not filled with spray-laden air. Rate of
travel should not exceed 2.5 miles per hour. A machine with too small an air
capacity will not replace the air contained in the tree with spray-ladened air,
thus poor coverage results. Small to medium sized trees can be row sprayed
while very large trees should be circled.


1Assistant Entomologist and Assistant Plant Pathologist


300 cc. 11/19/70








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Rates Fungicides and insecticides are recommended at specific rates of
application which have been found to be effective and nonphytotoxic under Florida
conditions. It is therefore very important to: 1. Know required rate of chemi-
cal per tree. 2. Calculate the gallons of spray per tree the machine will de-
liver at a given rate of travel. 3. Calculate the amount of chemical to add per
tank. Example: Duter is recommended at 0.08 pounds of 47.5% formulation per
tree. If 10 trees are sprayed per 100 gallons of water then 10 times 0.08
equals 0.8 pound of Duter required per 100 gallons or 4 pounds per 500 gallon
tank.

The following spray schedule (Table 1) will give commercial control of
important disease and insect pests. The schedule is designed for scab suscep-
tible varieties. Scab resistant varieties are susceptible to other leaf spot
diseases and should be sprayed with fungicides two or three times during the
summer. Where rosette is present, use a spray of neutral zinc (2 pounds) or
zinc sulphate (2 pounds of 65%). Zinc sulphate is very corrosive and will rust
machinery. It must be washed out with soap and water after use.


PRECAUTIONS


Parathion, EPN, and Guthion are especially toxic to man aid-shoUld beap-
plied 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, 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. See Table III on Residue Tolerances.









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TABLE I

PECAN SPRAY SCHEDULE FOR SCAB SUSCEPTIBLE VARIETIES1


SPRAY TIME OF APPLICATION
NO. (Approx. date for
North Florida)


PEST TO SPRAY MATERIAL
CONTROL For rates see
Table II


1. 1st prepollination
spray: When leaves
first show green.

Approx. April 1


Scab


Duter or Cyprex


Leaf
Case-
bearer


Do not use Cyprex on Moore
or Van Deman Var. Do not
graze livestock in treated
groves except where Mala-
thion or Bordeaux are used
alone. (If a spray program
was not followed last year
add an insecticide to con-
trol over-wintering Leaf
and Nut Casebearer.)


2. 2nd prepollination Scab Increase gallonage per tree
spray: When leaves as the foliage grows. Wet-
are half grown. Downy table powders such as Duter
Spot are sometimes physically
Approx. April 15 Duter or Cyprex incompatible with emulsifi-
Nursery able concentrates. Check
Blight compatibility of Duter with
EC insecticides before mix-
ing large amounts.

3. 1st cover spray: Scab Duter or Cyprex Proper timing for Nut Case-
When nuts are bearer is very important.
1/4" long. Powdery Add sulphur to Du- Dimethoate is effective
Mildew ter or Cyprex or principally against aphids.
Approx. May 1 use Bordeaux alone. Bordeaux is not compatible
Nut 1. Sevin or with any of the other mat-
Case- 2. Thiodan or erials listed.
bearer 3. Parathion or
4. EPN or
5. Guthion or
6. Malathion.
Mites Any of the above
except (1) & (2).
Aphids Dimethoate or any
of the above
except (1).
4. 2nd cover spray: Scab If weather is rainy, apply
Three weeks fungicide at two-week in-
after No. 3 Powdery tervals or increase rates
Mildew See 1st 1
Approx. May 21 Aphids cover spray
Mites


1For scab-resistant varieties add fungicide to sprays No. 3 and 6.


REMARKS









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TABLE I continued

PECAN SPRAY SCHEDULE FOR SCAB SUSCEPTIBLE VARIETIES1


SPRAY TIME OF APPLICATION
NO. (Approx. date for
North Florida)


PEST TO SPRAY MATERIAL
CONTROL For rates see
Table II


5. 3rd cover spray: Scab Begin checking small nuts
Three weeks Downy Spot for Shuckworm damage. See
after No. 4 Brown Leaf 4th cover spray for recom-
Spot mendation.
Approx. Mid June Powdery See first
Mildew cover spray
Mites
Aphids
6. 4th cover spray: Scab Apply second and third
First or second Downy Shuckworm sprays at two
week in July. Spot See first week intervals.
Brown cover spray
Leaf
Spot
Powdery
Mildew
Aphids
Mites
Shuckworm Guthion or EPN

7. 5th cover spray: Scab Apply EPN for pecan weevils
Last week in July Downy Spot when three or four adult
or first week in Brown Leaf weevils can be jarred from
August. Spot tree. Repeat application =
Powdery See first in three weeks.
Mildew cover spray
Aphids
Mites

Shuckworm Guthion or EPN
Pecan EPN
Weevils


8. 6th cover spray:
Mid August to
1st week in Aug.


Scab
Downy Spot
Brown Leaf
Spot
Powdery
Mildew
Mites P


See first
cover spray

arathion or
lalathion


Do not apply after shucks
start to open. If rainy
weather conditions exist,
it may be necessary to
apply 7th cover spray.


Shuckworm EPN or Guthion
Pecan
Weevil EPN
Black
Aphid Dimethoate


REMARKS








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TABLE II

AIIOUNT OF PESTICIDE REQUIRED PER 100 GALLONS1

Gallons of spray applied per medium sized tree


20 10
(Dilute) (2x)


6.66 5 4
(3x) (4x) (5x)


2.5 2
(8x) (10x)


Amount
Per tree Pounds of Wettable Powder Per 100 gallons of Water

Du-ter 0.08 Ib. 0.4 0.8 1.1 1.6 2.0 3.2 4.0
47.5% WP
Cyprex 0.02 1 2 2.7 4 5 8 10
65% 'WP
Sulfur or
Malathion 0.60 3 6 9 12 15 24 30
25% WP
Parathion 0.40 2 4 6 8 10 16 20
15% WP or
Guthion
25% WP or
EPN 25% WP or
Thiodan 50% WP or
Sevin 50% WPI

Ounces
Per tree Ounces of emulsifiable concentrate per 100 gallons of water

Parathion 4 20 40 60 80 100 160 200
2 Ib/gal EC or
Malathion
5 lb/gal EC
EPN 5 Ib/gal EC 2.5 12.5 25 37.5 50 62.5 100 125
Dimethoate 3.2 16 32 48 64 80 128 160
2.67 Ib/gal EC
(DeFend or Cygon)
Thiodan 9.6 48 96 144 192 240 384 480
2 lb/gal EC
EPN 2 lb/gal EC or 6.4 32 64 96 128 160 256 320
Guthion
2 lb/gal EC


pint 16 oz. = 473 milliliters
qt. = 32 oz. = 2 pints
gal. = 128 oz.= 4 qts. = 8 pts.
oz. = approx. 30 milliliters
Ib. = 16 oz.


.1 lb.
.4 lb.
.8 lb.


= 1.6 oz.
= 6.4 oz.
= 12.8 oz.


These figures are for medium size (25-35 ft.) trees. For larger trees multiply
either the amount of pesticide formulation per 100 gallons or gallons per tree by
1.25. For smaller trees multiply either gallons per tree or amount of pesticide
formulation by .75.


Chemical
inrmul a+ti nn


-- --











TABLE III

RESIDUE TOLERANCES AND LIMITATIONS FOR CHEMICALS RECOMMENDED FOR
PECANS IN THIS PUBLICATION


RESIDUE TOLERANCE
(PPM)


INTERNAL BETWEEN LAST APPLICATION AND
HARVEST AND OTHER RESTRICTIONS


Sevin --- Do not apply after shucks begin to open.


EPN 0.5 Do not apply within 21 days of harvest.


Guthion -- Do not apply after shucks begin to open.
Do not graze livestock in treated orchards.


Malathion 8.0 No time limitations.


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


Bordeaux Mixture Exempt No time limitations


Du-Ter -- Limit: 6.5 lbs. of 47.5% formulation/acre
Do not apply after shucks start to open.
Do not graze livestock in treated orchards.


Cyprex 0.3 Limit:7/0 Ibs. of 65.0% formulation/acre
Do not apply after shucks start to open.
Do not graze meat or dairy animals in
treated orchards.


Sulfur Safe No time limitations


Thiodan 0.2 Do not apply after shucks begin to open.
Do not graze meat or dairy animals in
treated orchards.


Dimethoate 0.1 Do not apply within 21 days of harvest.
Apply only with ground equipment. Do
not graze livestock in treated orchards.


CHEMICAL










TABLE IV

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)


Hydraulic


Air blast


4- 10


5 15


Mist blower


7 1/2 30



5


1 1/2 2


I __


~ __


2 1/2


Airplane




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