Title: Pecan insect and disease recommendations
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Title: Pecan insect and disease recommendations
Physical Description: Book
Creator: French, W. J.
Publisher: Agricultural Research Center, Agricultural Experiment Station, IFAS, University of Florida
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Bibliographic ID: UF00076495
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AGRICULTURAL RESEARCH CENTER MONTICELLO
\ ( AGRICULTURAL EXPERIMENT STATION IFAS
UNIVERSITY OF FLORIDA GAINESVILLE, FLORIDA

Research Report BB-1974-1 Febr, r i, A741 ip_ 1 f

REVISED
At R 1 1974
PECAN INSECT AND DISEASE RECOMMENDATIONS '1 1974

W. J. French1,2
I.F.A.S. Unv. o Fio

Disease and insects are often the limiting factors in the production of
pecans in Florida. The nut requires about 7 months to develop 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' pecan grower is fortun-
ate to have effective fungicides, insecticides, and improved spray equipment
available 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
established 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 some-
what predictable 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 avoided 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
concentrate 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 desired volume of spray in the proper pattern as is dictated by tree size.
Consult 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 insufficient 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-lad-
* dened air, thus poor coverage results. Small to medium sized trees can be row
sprayed while very large trees should be circled.

1-Assistant Plant Pathologist
2Prepared in collaboration with R. S. Mullin, Extension Plant Pathologist,
J. Brogdon, Extension Entomologist and S. S. Fluker,formerly Asst. Entomologist.











Rates Fungicides and insecticides are recommended at specific rates
of application which have been found to be effective and non-phytotoxic under
Florida conditions. It is, therefore, very important toil. Know required
rate of chemical per tree. 2. Calculate the gallons of spray per tree the
machine will deliver 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 pounds 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 time 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. Foliar nutri-
ent sprays should be applied separately; do not mix with fungicides or insect-
icides.

PRECAUTIONS

Parathion, EPN, Guthion, and Disyston are especially toxic to man 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, 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.


_.__










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 Scab DuTer, Cyprex or Do not use Cyprex on Moore
spray: When leaves Benlate or Van Deman Var. Do not
first show green Leaf graze livestock in treated
case- groves except where Malathion,
Approx. April 1 bearer and/or Benlate are used.
(If a spray program was not
followed last year add an
insecticide to control over-
wintering leaf and nut case-
bearer.)


2. 2nd prepollination Scab DuTer, Cyprex or Increase gallonage per tree
spray: When leaves Benlate as the foliage grows. Wet-
are half grown. Downy table powders such as DuTer
spot are sometimes physically in-
Approx. April 15 compatible with emulsifiable
Nursery concentrates. Check compat-
blight.. ibility of DuTer with EC in-
secticides before mixing large
amounts.


3. 1st cover spray:
When nuts are
1/4" long.

Approx. May 1


Scab DuTer, Cyprex or
Benlate
--------------------------
Powdery Add sulphur to Du-
mildew Ter or Cyprex or
use Bordeaux or
Benlate alone.
Nut


Proper timing for nut case-
bearer is very important.
Dimethoate is effective prin-
cipally against aphids. Bor-
deaux is not compatible with any
of the other materials listed.


case- 1. Thiodan or
bearer 2. Parathion or
3. EPN or
4. Guthion or
5. Malathion or
6. Sevin
7. Zolone
Mites Thiodan
Aphids Dimethoate, Disyston or
any of the above except
Sevin.


4. 2nd cover spray:
Three weeks
after No. 3

Approx. May 21


Scab

Powdery
mildew

Aphids

Mites


See first
cover spray


If weather is rainy, apply
fungicide at two-week in-
tervals or increase rates
by 1/2.


IFor scab-resistant varieties delete fungicide from all but sprays No. j ana o.


REMARKS


Sevin,









TABLE I continued

PECAN SPRAY SCHEDULE FOR SCAB SUSCEPTIBLE VARIETIES1


PEST TO SPRAY MATERIAL
CONTROL For rates see
Table II


0


REMARKS


5. 3rd cover spray: Scab Begin checking small nuts
Three weeks Downy spot for shuckworm damage. See
after No. 4 Brown leaf See first 4th cover spray for recom-
spot cover spray mendation.
Approx. mid-June Powdery
mildew
Mites
Aphids
6. 4th cover spray: Scab Apply second and third
First or second Downy shuckworm sprays at two
week in July. spot week intervals.
Brown See first
leaf cover spray
spot
Powdery
mildew
Aphids
Mites

Shuckworm Guthion, EPN, Zolone
or Parathion
7. 5th cover snrav: Scab. .


Last week in July
or first week in
August.


Downy spot
Brown leaf
spot
Powdery
mildew
Aphids
Mites

Shuckworm
Pecan
weevils


See first
cover spray


B


Apply riN or Sevin for pecar
weevils when three or four
adult weevils can be jarred
from tree. Repeat application
every 2 weeks for 3 applications.


Guthion, EPN, or Parathion or Zolone
EPN or Sevin


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


Scab
Downy spot
Brown leaf
spot
Powdery
mildew
Mites

Shuckworm
Pecan
weevil
Black
aphid


See first
cover spray


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


Thiodan


EPN, Guthion, or Parathion or Zolone
EPN or Sevin

Dimethoate or disyston or Zolone


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


-~-~--













Chemical
Formulation


TABLE II

AMOUNT OF PESTICIDE REQUIRED PER 100 GALLONS1

Gallons of spray applied per medium sized tree


20 10
(Dilute) (2x)


6.7 5 4 2.5 2
(3x) (4x) (5x) (8x) (10x)


Pounds
per tree Pounds of wettable powder per 100 gallons of water
Benlate 50% WP 0.08 0.4 0.8 1.2 1.6 2.0 3.2 4.0
Bordeaux mix-
ture (copper
sulfate and lime) .8 .2 4-1 8-2 *
Cyprex
65% WP 0.2 1 2 3.0 4 5 8 10
DuTer
47.5% WP .08 0.4 0.8 1.2 1.6 2.0 3.2 4.0
EPN 50% WP .40 1 2 3 4 5 8 10
Guthion
50% WP .40 1 2 3 4 5 8 10
Parathion
15% WP .40 2 4 6 8 10 16 20
Sevin
80% sprayable .60 3 6 9 12 15 24 30
Sulfur or
Malathion 25% WP .60 3 6 9 12 15 24 30
Thiodan 50% WP .40 2 4 6 8 10 20

Ounces Ounces of emulsifiable concentrate
per tree per 100 gallons of water
Dimethoate
2.67 lb./gal. EC
(DeFend or Cygon) 3.2 16 32 48 64 80 128 160
Disyston 6 EC 1.6 8 16 24 32 40 64 80
EPN 5 lb./gal. EC 2.5 12.5 25 37.5 50 62.2 100 125
EPN 2 lb./gal. EC 6.4 32 64 96 128 160 256 320
Guthion
2 lb./gal. EC 6.4 32 64 96 128 160 256 320
Malathion
5 lb./gal. EC 4 20 40 60 80 100 160 200
Parathion
2 lb./gal. EC 4 20 40 60 80 100 160 200
Thiodan
2 lb./gal. EC 9.6 48 96 144 192 240 384 480
Zolone
3 lb./gal. EC 4.3 21.3 42.6 63.9 85.2 106.5 170.4 213.0


1These figures
the amount of
smaller trees
.75.


1 pint = 16 oz. = 473 milliliters .1 ID. = .b o
1 qt. = 32 oz. = 2 pts. 14 lb. = 6.4 os
1 gal. = 128 oz. = 4 qts. = 8 pts. .8 lb. = 12.8 c
1 oz. = approx. 30 milliliters
1 lb. = 16 oz.
are for medium size (25-35 ft.) trees. For larger trees multiply either
pesticide formulation per 100 gallons or gallons per tree by 1.25. For
multiply either gallons per tree or amount of pesticide formulation by


Z.
z.
Dz.


*Low volume application of Bordeaux mixture is not recommended.


------ -~~










TABLE III

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


RESIDUE TOLERANCE
(PPM)


INTERVAL BETWEEN LAST APPLICATION
AND HARVEST AND OTHER RESTRICTIONS


Benlate 0.2 Do not apply after shucks split.


Bordeaux Mixture Exempt No time limitations.


Cyprex 0.3 Limit: 7.0 lbs. of 65% formulation/
acre. Do not apply after shucks
start to open. Do not graze meat
or dairy animals in treated orchards


Dimethoate


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


Disyston


DuTer


0.05


Registered for aphids only. Do not
apply within 30 days of harvest. Do
not graze livestock in treated or-
chards.


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


EPN 0.5 Do not apply within 21 days of harvest.


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


Malathion 8.0 No time limitations.


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


Sevin Extended No time limitations.


Sulfur Safe


CHEMICAL


No time limitations.










TABLE III
(continued)

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


RESIDUE TOLERANCE
(PPM)


INTERVAL BETWEEN LAST APPLICATION
AND HARVEST AND OTHER RESTRICTIONS


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


Zolone Do not apply more than 20 lbs.
(53.3 pints per acre per year).
Do not apply after shuck split.


CHEMICAL


~"







-8-


TABLE IV

GALLONS OF SPRAY BY TREE SIZE


TYPE OF EQUIPMENT GALLONS OF SPRAY BY TREE SIZE
Small Medium Large
(Under 25 feet) (25-35 feet) (over 35 feet)

Hydraulic 15 20 30

Air blast 4 10 5 15 7 1/2 30

Mist blower 3 4 5

Airplane 1 1/2 2 2 1/2




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