Bugging Out

Stormy Sparks and John RubersonUniversity of Georgia, Tifton

General IPM (in organic production)

• In Georgia, lots on insects• In organics, limited “rescue treatments”• “Preventive management” is required for

most insect pests• Management plans based on expected

pests (crop selection, your history)• In-season management based on frequent

monitoring of pest populations • Market effects tolerance

Scouting Vegetables

Integrated Pest Management

In-season Management

Crop Selection

Variety Selection

Sanitation, Cover Crops, Soil Preparation, Fertilization

Planting Date

Pest Complex Natural Enemies

Pest-free Transplants

Harvest Date

Trap Cropping,

Farmscaping

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cale

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In-season Management:

•Fertilizer management

•Water management

•Crop development

•Scouting and therapeutic tactics for weeds, insects, diseases

Know Your Enemy

• Pest identification– Biology

• Life history, mobile stages, overwintering, damaging stages, “weakness” in pest biology

– History• Crop specific problems, local history (Extension

Service, other growers, etc.), your history (experience; field by field basis)

Know Your Enemy

• Pest identification– Damage

• Stage that causes injury• Plant stages susceptible to injury• Type of damage (holes, plant deformity,

discoloration, etc.)• Disease transmission

Identifying Insects

• Adults vs immatures• Common insects vs the obscure• Picture book vs insect keys• Distance Diagnostics through Digital

Imaging (DDDI - Extension Service)• E-mail

Identifying Insects

• From pictures or descriptions– Crop and type of damage– Whole insect (for common insects only)– General group is usually easy– Specifics requires specific information

• Mouthparts• Legs (or parts of legs)• Antennae• Wings (number, type, venation)

Identifying Insects

• Submitting samples– Prefer multiple specimens– Prefer adults over immatures (but varies)– Live vs dead– Hard bodied insects

• Do not place loosely in envelope• Pad to protect from breakage

– Soft bodied insects• Place in vial in alcohol (not water)

Identify Insects

• Identification is the key to what is known about any specific insect

• Is it is pest?• Allows access to known management

strategies– Curative vs preventative

Resources/References

University publications and web sites.

Some Pests

Caterpillars

©Pixar

Caterpillars

• Large and important group of insects• Immatures damage plants• Chewing mouthparts (tissue removed)• Damage

– Defoliators (diamondback moth, armyworms, cabbageworms)

– Stem borers (vine borers, European corn borer)– Fruit feeders (corn earworm, pickleworm)

• Moderate to high mobility; can be local

Caterpillar StrategiesSolitary Gregarious

External feeder

-Diamondback moth-Cabbage looper-Imported cabbageworm

-Armyworms-Cross-striped cabbageworm

Internal feeder

-Pickleworm-Corn earworm-Squash vine borer

-Armyworms-Pickleworm

Imported Cabbageworm

• Solitary (sometimes small groups) eggs, stand on end

• Larvae green and velvety, with yellow line down back (except L5), 5 instars, leaf feeders

• Adults are white/yellowish butterflies with black spots in wings, active during day

• 6-8 generations per year (about 20-40 days)

Imported CabbagewormEgg

Larva

Russ OttensPupa

Adult

Diamondback Moth

• Solitary (sometimes small groups) eggs, leaf feeders

• Larvae voracious feeders, 4 instars, cryptic coloring, rapid wigglers

• Adults active, lay eggs dusk to midnight• 12-15 generations per year (about 20-35

days)

Diamondback Moth

Canola Council of Canada

Agriculture and Agri-Food Canada

Whitney Cranshaw

Egg

Larva

Whitney Cranshaw

Pupa

Adult

Melon and Pickleworms

• Eggs laid in small groups (2-7), deposited at night on buds, leaves, stems , flowers

• Larvae leaf, blossom, and fruit feeders, 5 instars

• Pupate in dry (pickle) or green (melon) leaves

• 6-8 generations per year (about 30 days), moths night active

Pickleworm

Natasha Wright

Clemson University

Alton Sparks

Melonworm

Alton Sparks

Alton SparksAlton Sparks

University of Florida

Larva

Damage

Adult

Cross-striped Cabbageworm

• Eggs laid in small groups (3-25) on leaf undersides

• Larvae leaf and terminal feeders, 4 instars,• Pupate in soil• 5-8 generations per year (about 20-60

days)

Cross-striped Cabbageworm

Clemson University Hannah Nendick-MasonDamage

Larva

Corn Earworm

• Eggs laid singly (3-5), fruit feeders• Larvae leaf to fruit feeders, 5-6 instars,

cannibalistic when older• Pupate in soil• Adults active at night, lay eggs after dusk• 4-6 generations per year (about 30-40

days)

Corn Earworm

Auburn Univ.NC State Univ.

Dorothy Pugh

Larva

Egg

Adult

Pupa

General Caterpillar Management• Host plant resistance – Consider resistant

crops or varieties, some available• Biological control – Egg, larval, and pupal

parasitism; predation; pathogens• Cultural Control – Planting date timing;

sanitation; trap cropping; row covers (melon/pickle)

• Chemical controls – Bt generally effective for external feeders; spinosad also; neem good to marginal; pyrethrins marginal; diatomaceous earth mixed results (general “toxin”)

BeetlesMike Boone

Beetles

• The largest group of insects• Adults and/or immatures damage plants• Chewing mouthparts (tissue removed)• Damage

– Defoliators (leaf beetles, cucumber beetles)– Soil pests (white grubs, cucumber beetels)– Weevils (some external, some internal)

• Mobility varies (none migratory, some home-grown)

Beetle

• “Hard shelled” (sclerotized forewings)• Good and bad can look similar

– Leaf beetles vs Lady beetles– Know all stages

• Larvae (and pupae) vary in appearance and location– Leaf beetles vs grubs

• Biology also diverse

Cucumber beetles

• Multiple species (spotted, striped, banded)• Wide host range (like pollen and flowers)• Adults are defoliators, can damage fruit

– Can transmit disease• Larvae in soil (feed on roots)(rindworm)• Adults overwinter (long lived)• Egg to adult in 4-6 weeks• 2 to 3 generations per year

Cucumber beetles

Cucumber beetles

• Management– Use of transplants– Delayed planting in Spring– Traps or baiting– Regional control program

Flea Beetles

• Multiple species (some fairly host specific)• Adults chew shot-holes in leaves• Jumping hind legs• Larvae in soil (root crops)• Damage severity varies with crop

– Peppers (seedling damage) vs Eggplant– Brassica (season long)– Disease transmission

Flea Beetles

Flea Beetles

• Management (varies with crop)– Use of transplants– Delayed planting (for rapid growth)– Row covers

Weevils

• Largest group of beetles• Appearance and biology vary• Vegetable weevil vs Pepper weevil

Vegetable weevil

Pepper weevil

Vegetable Weevil• Host plant resistance

– Butternut 23, Summer Crookneck, Early Prolific Straightneck, and Early Yellow Summer Crookneck squash (NCSU)

• Biological control – Some egg parasitism, difficult• Chemical controls – limited value• Trap cropping – Plant more susceptible plant nearby

(e.g., a zucchini variety)• Bagging of fruit – difficult, time consuming, and limited

efficacy!• Migratory pest – Spring production avoids

Flea Beetles

• Host plant resistance• Biological control – Some egg parasitism,

difficult• Chemical controls – limited value• Trap cropping – Plant more susceptible

plant nearby (e.g., a zucchini variety)• Bagging of fruit – difficult, time consuming,

and limited efficacy!• Migratory pest – Spring production avoids

Cucumber Beetles

• Host plant resistance• Biological control – Some egg parasitism,

difficult• Chemical controls – limited value• Trap cropping – Plant more susceptible

plant nearby (e.g., a zucchini variety)• Bagging of fruit – difficult, time consuming,

and limited efficacy!• Migratory pest – Spring production avoids

Aphids and Whiteflies©1999 Zunke & EisenbackJ. Ruberson

Aphids and Whiteflies• Small and soft-bodied• Large number of species that are quite similar in

appearance• Slow, but high mobility – “plankton”• Piercing/sucking feeders• Important disease vectors of various crops• Terrific capacity for increase• Produce copious amounts of honeydew – sooty

mold• Tend to respond to plant nitrogen – healthy

plants cope better

Aphids• Many pests have wide host range• Mostly female and live-bearing – rapid

population growth; overwinter as eggs• Typically 4-5 nymphal instars• Winged stages are critical for long-range

movement• Can directly damage plant as “parasites”• Some can indirectly damage crops through virus

transmission (mosaic viruses, potyviruses, others)

AphidsJ. Ruberson

Zucchini Yellows VirusZucchini Yellows Virus

Todd Vagts

Marlin Rice

Sooty Mold

Winged adult

Whiteflies• Wide host range• Eggs tiny and hard to see; first immature stage

is mobile, but remainder are sessile• Four nymphal instars• Adults are highly mobile• Can directly damage plant as “parasites”; plant

weakening and defoliation, silverleaf• Can transmit geminiviruses (e.g., tomato leaf

curl)• Probably 12-14 generations per year; love hot

and dry

Whiteflies

Magnus Gammelgaard

Marlin Rice

Whitefly Damage

David Riley

Ric Bessin

Tomato Leaf Curl Silverleaf

Aphid and Whitefly Management

• Host plant resistance – Consider resistant crops or varieties for insects, but perhaps especially for diseases, some available; hairy varieties and whiteflies

• Biological control – Egg, nymphal parasitism; predation; pathogens; can be quite effective, but also can be tough to keep up

• Cultural Control – Host free periods/locales; sanitation; mulches/residue (background); row covers

• Chemical controls – Insecticidal soaps, light mineral oils (test first!)

Thrips

Thrips Damage

• Adults and larvae damage plants• Location on plant varies with species

– Tobacco thrips vs Western flower thrips– Thigmotactic

• Single mandible (rasping/piercing)• Plant stunting, deformities• Fruit damage • Disease vector – Tomato Spotted Wilt

Thrips Damage

Thrips Management

• Wide host range (weeds, etc.)– Sanitation– Peak populations in Spring (start on weeds)

• Not all species are damaging– F. tritici – very common, grass species– Predacious thrips

• Insecticidal soaps– Foliar vs flower thrips

• Neem – “preventive”, migration?

True Bugs

Carolyn Stapleton

Texas A&M Univ.

USDA

David Kleiman

True Bugs

• Challenging pests – damage often detected before bugs

• Adults and immatures damage plants• Sucking mouthparts• Damage

– Flower buds (damage developing flowers)– Fruit (attack seeds, moist tissues; catfacing

and tissue necrosis)• High mobility

True Bugs

• Well-developed wings with ‘X’ on back• Immatures resemble adults in general

form• Mixture of pests, beneficials, ‘tweeners’• Good and bad can look similar

– Predatory stink bugs and pest brown stink bugs

• Broad based in the landscape

Stink Bugs, Leaf-footed Bugs

• Highly mobile and wide host ranges• Eggs barrel-shaped and laid in groups on

plant surface• Nymphs pass through 5 instars, no pupa;

feed throughout; attack tender growing points, flower buds, and fruit

• Adults tend to be long-lived

Stink Bugs, Leaf-footed BugsRuss OttensDebbie Roos

Russ Ottens

Ron Smith

Herb Pilcher

Marlin RiceEggs

Nymphs

Adults

Plant Bugs

• Highly mobile and wide host ranges• Insert eggs in plant• Nymphs pass through 5 instars, no pupa;

feed throughout; attack tender growing points, flower buds (bud “blasting”, and fruit

• Adults tend to be long-lived• Good, bad, and indifferent species

Plant Bugs

Scott Stewart

ARS-USDA

ARS-USDAUniv. of Tennessee

Rob’s Plants

Nymphs

Adults

Egg

Bug Damage

Ric Bessin

Gordon Johnson

Univ. of Florida

Bug Management

• Host plant resistance – Some resistance, but limited

• Biological control – Egg and adult parasitism (some nymphal); predation; pathogens

• Cultural Control – Planting date timing; sanitation in and around; trap cropping (alfalfa, millet, sorghum, sunflower); row covers

• Chemical controls – Soaps on immatures; rotenone or sabidilla*

Various Soil Pests

Various Soil Pests

White grubs

Cutworm Cucumber Beetles

Wireworm

Soil Pest Management

• Most problems are home-grown• Sanitation, sanitation, sanitation

– Avoid prior turf areas, weedy fallow fields• Physical control• Crop rotation (including fallow) • Organic matter – seedcorn maggot• Transplants, plant when warmer

Natural Enemies

Biological Control - Parasitoids

• Trichogramma pretiosum, Trissolcus basalis, others– Attack eggs, eggs-larvae– Some commercially available

Jack Kelly ClarkTrichogramma on egg

Trissolcus on eggs

Copidosoma attacking

looper egg

Killed

looper

Biological Control - Parasitoids

• Diadegma insulare, Microplitis plutellae, Cotesia vestalis (=plutellae)*– Attack larvae, reduce feeding

J. Ruberson

Diadegma adult and pupa

Microplitis adult

and pupa

Cotesia adult and pupa

Biological Control - Parasitoids

• Cotesia spp., others– Attack larvae, pupae– Some commercially available

Whitney Cranshaw

Debbie Waters

Lespesia adult,

Parasitic fly

Pteromalus attacking

host pupa

Cotesia pupae and adult

• Lysiphlebus sp., Eretmocerus spp., others

Biological Control - Parasitoids

Jack Kelly Clark

Lysiphlebus adult and mummiesDiadegma adults and pupa

Biological Control - Predators

• Lacewings

J. Ruberson

USDA

David Cappaert

Green lacewing egg

Green lacewing larva

Green lacewing adult

Brown lacewing adult

• Predators: Lady beetles, hoverflies

Biological Control - Predators

Jack Kelly Clark

Jack Kelly Clark

Russ Ottens

Ladybeetle adult

Ladybeetle larva

Hoverfly larva

Hoverfly adult

Biological Control - Predators• Predators: Damsel bugs, big-eyed bugs,

assassin bugs, pirate bugs

Jorge B TorresJack Kelly Clark

Jack Kelly Clark

J. Ruberson

Damselbug adult

and nymphBig-eyed bug adult

Assassin bug adult

Pirate bug adult

Biological Control - Predators

• Predators: Earwigs, ants, paper wasps and others

Russ Ottens

J. Ruberson

J. Ruberson J. Ruberson

J. Ruberson

Fire ants

Robber fly Earwig

Paper wasp

Biological Control - Predators

• Spiders: Mostly generalists

Russ Ottens

J. Ruberson

J. Ruberson

J. Ruberson

Theridion spider

Wolf spider

Green lynx spider

eating good guys

Russ Ottens

Biological ControlsParasitoids Predators

Caterpillars Numerous for external, limited internal

Numerous for external, limited internal

Beetles Various egg and larvae, some pupae

Bugs, other beetles

Aphids Lysiphlebus, Aphelinus, others

Lacewings, Lady beetles, hover flies

Whiteflies Eretmocerus, Encarsia, others

Lacewings, Lady beetles, hover flies, bugs

Thrips Very limited Pirate bugs, predatory mites, other thrips

True Bugs Various egg, some adult parasitism

Various depending on species

Wildcards: Spiders

Biological Control - Pathogens

• Fungi, Viruses, Bacteria, Nematodes, Protozoa

Fungi

Beauveria bassiana

Metarhizium anispoliae

Paecilomyces

Beauveria bassiana

Metarhizium anisopliae

Biological Control - Pathogens

• Fungi, Viruses, Bacteria, Nematodes, Protozoa

Virus

NematodesGemstar

Steinernema and Heterorhabditis

Useful References• ATTRA: http://attra.ncat.org/attra-

pub/farmscape.html (free!)

• “Natural Enemies Handbook” ($16.47 on Amazon)

• “Manage Insects on Your Farm”– http://www.sare.org/publications/insect.htm

• “Handbook of Natural Insect and Disease Control” ($16.29 on Amazon)

Useful References• “Handbook of Vegetable Pests” by John

Capinera ($170.00! On Amazon)

• “Insect and Related Pests of Vegetables”, NCSU ($10.00 from NCSU )

• http://ipm.ncsu.edu/AG295/html/index.htm