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Pecan Insect and disease recommendations

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Title:
Pecan Insect and disease recommendations
Creator:
Fluker, Sam S.
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Big Bend Horticultural Laboratory, University of Florida
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English

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


PECAN INSECT AND DISEASE RECO11MENDATIONS HUME LIBRARY

S. S. Fluker and W. J. Frenchl 7 1 271


Diseases and insects are often the limiting factors107-i". p1LMmtAPF!i Z - i d a of pecans in Florida. The nut requires about 7 months to kievplnp 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 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 somewhat 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-ladened air, thus poor coverage results. Small to medium sized trees can be row sprayed while very large trees should be circled.'


BIG BEND HORTICULTURAL LABORATORY
Monticello, Florida


1 Assistant Entomologist and Assistant Plant Pathologist


300 cc. 11/19/70





-2-


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 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 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 susceptible 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 afid,-shoUd'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.









-3-


TABLE I

PECAN SPRAY SCHEDULE FOR SCAB SUSCEPTIBLE VARIETIES


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


PEST TO SPRAY MATERIAL CONTROL For rates see
Table II


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

Approx. April 1


Scab


Duter or Cyprex


Leaf Casebearer


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


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

3. Ist cover spray: Scab Duter or Cyprex Proper timing for Nut CaseWhen 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 I use Bordeaux alone. Bordeaux is not compatible
Nut 1. Sevin or with any of the other matCase- 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 inafter No. 3 1stdery tervals or increase rates

Approx. May 21 Aphids cover spray by 1/2.
Mites


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


REMARKS









-4-


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 recomSpot 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
Malathion


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








-5-


TABLE II

AMOUNT OF PESTICIDE REQUIRED PER 100 GALLONS1

Gallons of spray applied per medium sized tree


20 10


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 lb. 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% I'

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

Parathion 4 20 40 60 80 100 160 200
2 lb/gal EC or Malathion
5 lb/gal EC EPN 5 lb/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 lb/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
Guthi on
2 lb/gal EC


pint w 16 oz. = 473 milliliters qt. = 32 oz. = 2 pints gal. - 128 oz.= 4 qts. f 8 pts. oz. = approx. 30 milliliters lb. = 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











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 lbs. 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.


CHENI CAL





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


5 - 15


7 1/2 - 30



5


Air blast


4 - 10


Mist blower


2 1/2


1 1/2 2


Airplane




Full Text
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PAGE 1

i BIG BEND HORTICULTURAL LABORATORY Monticello, Florida Big Bend Hort. Lab. Mimeo Report BBL 71-2 November 19, 1970 S.S. Fluker andH. J. French 1 , Diseases and insects are often the limiting factors~ tf.,~1:@. pf-t~t:ePtf!J!'ida , of pecans in Florida. The nut requires about 7 months to fctevelop 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." 1 Assistant Entomologist and Assistant Plant Pathologist 300 cc. 11/19 /70

PAGE 2

-2Rates 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 O .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. PRECAtrrIOUS Parathion, EPN, and Guthion are especially toxic to man arid-shoutd be ~p plied only by properly trained and equipped operators. Read the ~ntire 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.

PAGE 3

-3TABLE I PECAN SPRAY SOIEDULE FOR SCAB SUSCEPTIBLE VARIETIES 1 SPRAY TIME OF APPLICATION PEST TO SPRAY 't--f..ATERIAL NO. (Approx. date for CONTROL For rates see 1. 2. 3. North Florida) Table II 1st prepollination spray: When leaves first show green. Approx. April 1 2nd prepollination spray: When leaves are half grown. Approx. April 15 1st cover spray: When nuts are 1/4 11 long. Approx. May 1 Scab Leaf Case bearer Scab Downy Spot Nursery Blight Scab Powdery Mildew Nut Case bearer Hites Aphids Duter or Cyprex Duter or Cyprex Duter or Cyprex Add sulphur to Du ter or Cyprex or use Bordeaux alon~. 1. Sevin or 2. Thiodan or 3. Parathion or 4. EPH or 5. Guthion or 6. Halathion. Any of the above except (1) & (2). Dimethoate or any of the above RE?--'.ARKS 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.) Increase gallonage per tr~e as the foliage grows. Wet table powders such as Duter are sometimes physically incompatible with emulsifi able concentrates. Check compatibility of Duter with EC insecticides before mix ing large amounts. Proper timing for Nut Case bearer is very important. Dimethoate is effective principally against aphids. Bordeaux is not compatible with any of the other mat erials listed. __ _ __ _ _______________ e_x_c_ep._t_( __ l~)_. _________________ _ 4. 2nd cover spray: Three weeks after No. 3 Approx. May 21 Scab Powdery Mildew Aphids Mites See 1st cover spray If weather is rainy, apply fungicide at two-week in tervals or increase rates by 1/2. 1 For scab-resistant varieties add fungicide to sprays No. 3 and 6.

PAGE 4

-4TABLE I continued PECAN SPRAY SCHEDULE FOR SCAB SUSCEPTIBLE VARIETIES! SPRAY TIME OF APPLICATION NO. (Approx. date for 5. 6. 7. a. North Florida) 3rd cover spray: Three weeks after No. 4 Approx. Mid June 4th cover spray: First or second week in July. 5th cover spray: Last week in July or first week in August. 6th cover spray: Hid August to 1st week in Aug. PEST TO CONTROL Scab SPRAY MATERIAL For rates see Table II Downy Spot Brown Leaf Spot Powdery See first Mildew cover spray Mites hids Scab Downy Spot See first Brown cover spray Leaf Spot Powdery Mildew Aphids Mites Shuckworm Guthion or EPN Scab Downy Spot Brown Leaf Spot Powdery See first Mildew cover spray Aphids Hites Shuckworm Guthion or EPN Pecan EPN Weevils Scab Downy Spot Brown Leaf Spot See first Powdery cover spray Mildew Mites Parathion or Malathion Shuck.worm EPN or Guthion Pecan Heevil EPN Black Aphid Dimethoate REMARKS Begin checking small nuts for Shuckworm damage. See 4th cover spray for recom mendation. Apply second and third Shuckworm sprays at two week intervals. Apply EPN for pecan weevils when three or four adult weevils can be jarred from tree. Repeat application in three weeks. Do not apply after shucks start to open. If rainy weather conditions exist , it may be necessary to apply 7th cover spray.

PAGE 5

-S TABLE II AHOUNT OF PESTICIDE REQUIRED PER 100 GALLONS l Gallons of sprav applied per medium sized tree Chemical Formulation 20 10 6.66 5 4 2.5 2 (Dilute) (2x) (3x) (4x) (5x) (8x) (lOx) Amount Per tree Pounds of Wettable Powder Per 100 gallons of Water Du-ter 0.08 lb. 0.4 0.8 1.1 1.6 2.0 3.2 47 .5% WP Cyprex 0.02 1 2 2.7 4 5 8 65% ' WP Sulfur or Malathion 0.60 3 6 9 12 15 24 25% WP Parathion 0.40 2 4 6 8 10 16 15% WP or Guthion 25% WP or EPN 25% WP or Thiodan 50% HP or Sevin 50% WP Ounces Per tree Ounces of emulsifiable concentrate per 100 gallons Parathion 4 20 40 2 lb/ gal EC or Malathion 5 lb/gal EC EPN 5 lb/gal EC 2.5 12.5 25 Dimethoate 3.2 16 32 2.67 lb/gal EC (DeFend or Cygon) Thiodan 9.6 48 96 2 lb/ al EC EPN 2 lb/gal EC or 6.4 32 64 Guthion 2 lb/gal EC 1 pint 16 oz. = 473 milliliters 1 qt. = 32 oz.= 2 pints 1 gal.= 128 oz.= 4 qts. 8 pts. 1 oz.= approx. 30 milliliters 1 lb. = 16 oz. 60 37.5 48 144 96 80 100 160 50 62.5 100 64 80 128 192 240 384 128 160 256 1 lb = 1. 6 oz 4 lb. = 6.4 oz. .8 lb.~ 12.8 oz. 4.0 10 30 20 of water 200 125 160 480 320 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.

PAGE 6

-------------------------------------------, OIEMICAL Sevin EPN Guthion Malathion Parathion TABLE III RESIDUE TOLERANCES AND LIMITATIONS FOR CHEMICALS RECOMMENDED FOR PECANS IN THIS PUBLICATION RESIDUE TOLERANCE (PPH) 0.5 8.0 nlTERNAL BETWEEN LAST APPLICATION AND HARVEST AND OTHER RESTRICTIONS Do not apply after shucks begin to open. Do not apply within 21 days of harvest. Do not apply after shucks begin to open. Do not graze livestock in treated orchards. No time limitations. Do not apply within 15 days of harvest or after shucks open. Bordeaux Uixture Exempt No time limitations Du-Ter Cyprex 0.3 Sulfur Safe Thiodan 0.2 Dimethoate 0.1 Limit: 6.5 lbs. of 47.5% formulation/acre Do not apply after shucks start to open. Do not graze livestock in treated orchards. Limit:7t0 lbs. of 65.0% formulation/acre Do not apply after shucks start to open. Do not graze meat or dairy animals in treated orchards. No time limitations Do not apply after shucks begin to open. Do not graze meat or dairy animals in treated orchards. Do not apply within 21 days of harvest. Apply only with ground equipment. Do not graze livestock in treated orchards.

PAGE 7

TYPE OF EQUIPMENT Hydraulic Air blast Mist blower Airplane -r TABLE IV GALLONS OF SPRAY BY TREE SIZE GALLONS OF SPRAY BY TREE SIZE Small (Under 25 feet) 15 4 10 3 11/2 Medium (25-35 feet) 20 5 15 4 2 Large (Over 35 feet) 30 7 1/2 30 5 2 1/2