Foliage Pests of PecanFoliage Pests of Pecan

Will HudsonWill Hudson

Extension EntomologistExtension Entomologist

Objective : Protecting Pecan FoliageObjective : Protecting Pecan Foliage

Budbreak to Harvest is Budbreak to Harvest is 8 months 8 months Pecan foliage has to Pecan foliage has to be conserved and be conserved and protected from insects protected from insects and diseases to and diseases to produce photosynthate produce photosynthate for next season’s crop for next season’s crop and to reduce the and to reduce the amplitude of alternate amplitude of alternate bearing cyclebearing cycle

Foliage PestsFoliage Pests

AphidsAphids– Yellow Pecan AphidYellow Pecan Aphid– Black-margined Pecan AphidBlack-margined Pecan Aphid– Black Pecan AphidBlack Pecan Aphid

MitesMites

PhylloxeransPhylloxerans

CaterpillarsCaterpillars

AphidsAphids

Short life cycle and high reproductive Short life cycle and high reproductive potential result in explosive population potential result in explosive population growth in favorable conditionsgrowth in favorable conditions

Lots of natural enemies, so biological Lots of natural enemies, so biological control can be effectivecontrol can be effective

Scouting is criticalScouting is critical

Both systemic and contact insecticides are Both systemic and contact insecticides are usedused

Aphid Abundance by Date in Untreated Aphid Abundance by Date in Untreated TreesTrees

0

20

40

60

80

100

Aphi

ds/c

omp.

leaf

YPA BMA BPA

Predicting Aphid OutbreaksPredicting Aphid OutbreaksPopulation Growth - Days to DoublePopulation Growth - Days to Double

aphidaphid

JuneJune

28 C28 C

JulyJuly

27 C27 C

AugustAugust

28 C28 C

Sept.Sept.

27 C27 C

Oct.Oct.

23 C23 C

BMABMA 1.81.8 1.61.6 1.71.7 1.81.8 2.12.1

YPAYPA 2.12.1 2.02.0 2.02.0 2.02.0 2.42.4

BPABPA 2.92.9 2.72.7 2.72.7 2.82.8 3.43.4

Kaakeh and Dutcher. 1992. Environ. Entomol. 21: 632-9.

Scouting for AphidsScouting for Aphids

Orchards should be scouted weekly Orchards should be scouted weekly

Examine a “random” sample of terminals Examine a “random” sample of terminals from trees throughout the orchardfrom trees throughout the orchard

Know how to identify the aphidsKnow how to identify the aphids

Recognize beneficialsRecognize beneficials

Know your trees and orchard historyKnow your trees and orchard history

Keep up!Keep up!

Yellow Pecan AphidYellow Pecan Aphid

May be found any May be found any time during the time during the seasonseason

Winged adults are not Winged adults are not always presentalways present

Populations usually Populations usually peak in late summerpeak in late summer

““Threshold” is 20 per Threshold” is 20 per compound leaf compound leaf

Black Pecan AphidBlack Pecan Aphid

Populations usually Populations usually peak in late seasonpeak in late seasonSome varieties are Some varieties are very susceptible to very susceptible to damagedamageFeeding causes Feeding causes chlorosis and leaflets chlorosis and leaflets drop prematurelydrop prematurelyThreshold is 15% 0f Threshold is 15% 0f terminals with >1terminals with >1

Lady BeetlesLady Beetles

LADY BEETLE PUPALADY BEETLE PUPA

LacewingsLacewings

Green Lacewing EggsGreen Lacewing Eggs

BROWN LACEWINGBROWN LACEWING

BROWN LACEWING LARVABROWN LACEWING LARVA

LACEWING CAMOUFLAGELACEWING CAMOUFLAGE

SYRPHID FLY ADULT AND SYRPHID FLY ADULT AND LARVALARVA

Pecan Aphid Chemical ControlPecan Aphid Chemical Control

Soil Treatment – Season-long chemical Soil Treatment – Season-long chemical control is effective with application of control is effective with application of systemic insecticide – Temik or Admiresystemic insecticide – Temik or Admire

Foliage Treatment - Reliance on beneficial Foliage Treatment - Reliance on beneficial insects for control through early August insects for control through early August and foliage application of Dimethoate, and foliage application of Dimethoate, Fulfill, Centric, Provado + Lorsban, etc. Fulfill, Centric, Provado + Lorsban, etc. from then until Octoberfrom then until October

InsecticideApplication Methods

Black-margined Aphid Abundance in Black-margined Aphid Abundance in Insecticide-Treated and Untreated TreesInsecticide-Treated and Untreated Trees

02468

1012141618

aphi

ds p

er c

ompo

und

leaf

ControlAdmire - 16Provado - 3.5

Treatment - oz form/a

Black Pecan Aphid Abundance in Black Pecan Aphid Abundance in Insecticide-Treated and Untreated TreesInsecticide-Treated and Untreated Trees

0

5

10

15

20

25

30

35

aphi

ds p

er c

ompo

und

leaf

ControlAdmire - 16 Provado - 3.5

Treatment –oz form/a

To Treat or Not To TreatTo Treat or Not To Treat

What aphid?What aphid?

What else is there?What else is there?– BeneficialsBeneficials– Other pestsOther pests

Weather conditionsWeather conditions

CultivarCultivar

Time of the seasonTime of the season

Pecan Leaf Scorch MitePecan Leaf Scorch Mite

Feeding causes Feeding causes “scorching” effect on “scorching” effect on leavesleavesMites are usually found Mites are usually found on underside of leafleton underside of leafletInfestations often start Infestations often start low in the center of the low in the center of the treetreeSymptoms look like some Symptoms look like some diseasesdiseasesDicofol, Vendex, Temik Dicofol, Vendex, Temik provide controlprovide control

Pecan Leaf Scorch MitePecan Leaf Scorch MitePhoto by HC Ellis

CaterpillarsCaterpillars

Most foliage feeders are minor in Most foliage feeders are minor in importanceimportance

Usually infest only a few treesUsually infest only a few trees

Many insecticidal options are labeled Many insecticidal options are labeled

Sprays for other insects usually get these Sprays for other insects usually get these alsoalso

Walnut CaterpillarWalnut Caterpillar

Fall WebwormFall Webworm

PhylloxeraPhylloxera

Two types – stem and leafTwo types – stem and leaf

““Sucking bugs”, related to aphidsSucking bugs”, related to aphids

One generation per yearOne generation per year

Once the galls form, control is difficultOnce the galls form, control is difficult

Treat at bud-break, or go systemicTreat at bud-break, or go systemic

Leaf PhylloxeraLeaf Phylloxera

Stem PhylloxeraStem Phylloxera

Extension ProgramsExtension Programs

Annual spray guideAnnual spray guideScout school odd yearsScout school odd yearsField day Sep 8Field day Sep 8Telephone hotline and direct lineTelephone hotline and direct line– 1-800-851-28471-800-851-2847

Websites and handbookWebsites and handbook– http://sacs.cpes.peachnet.edu/pecan/http://sacs.cpes.peachnet.edu/pecan/

Grower association meetingsGrower association meetings– GPGA annual meeting May 5 in PerryGPGA annual meeting May 5 in Perry