organic approaches to insect pest management on vegetable crops · 2019. 3. 27. · insect pest...

Organic Approaches to Insect Pest Management

on Vegetable Crops

Celeste WeltyExtension Entomologist

March 2019

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The goal

The reality

Search for a weak link in life cycle

Ecological contextThe crop field:• Crops• Pests• Natural enemiesThe agricultural

landscape:• Crop fields• Woodlands• Hedgerows• Ditches

Crop ecology: is food chain balanced or unbalanced?

producer (mustard)

herbivore (imported cabbage-

worm)

herbivore (cabbage maggot)

carnivores (parasitoid

wasps)

Pest management actions• Strategies–Do nothing–Eradication–Prevention –Suppression

• Tactics–Cultural–Mechanical–Biological–Behavioral–Microbial–Chemical

Issues of scale• Large farms vs small farms vs gardens• Monoculture vs polyculture

• Same crop• Same possible pests

• Different intensity of infestation• Different tactics• Different economics

Organic vs other approaches• Willingness to use tactics:–More knowledge intensive –More labor intensive –More expensive (?)– Include chemicals: yes or no?

• More concern with restoring checks & balances• More willing to tolerate damage

Biological Control• Control of pest by other

organisms that act as natural enemies–Conservation–Augmentation

• Common natural enemies–Predators–Parasitoids

Biological Control:Predators

• Develop at expense of more than one prey item• Predator often larger

than prey• Prey usually killed &

consumed quickly

Predatory Beetles

• Lady beetles

• Ground beetles

• Rove beetles• Soldier beetles

adultadult

larva

adult

larva

adult

Predatory True Bugs

• Stink bugs–Spined soldier bug– Twospotted stink bug

• Flower bugs–Minute pirate bug– Insideous flower bug

• Damsel bugs• Assassin bugs

adult

nymph

Predatory Flies

• Hover flies (flower flies)

• Aphid midges

• Robber flies

larvaadult

larva

adult

Lacewings

• Green lacewings

• Brown lacewings

Other Predators

• Wasps:–Yellowjackets

• Thrips:–Black hunter thrips

• Mites:–Phytoseiid mites

Biological Control: Parasitoids

• Develop at expense of a single host• Lay egg in or on host insect • Host is usually killed slowly• Enemy usually smaller than host

Parasitoids: typical life cycle

Categories of parasitoids• Endoparasites–Develop inside body of host

• Ectoparasites–Feed externally, attach to outside of host

Life Cycle of Parasitoid

Hyposoterwasp attacking caterpillar

Life Stages of Parasitoid

Trichogrammawasp attacking caterpillar egg

Parasitoids• Some wasps–Braconid wasps•On hornworm: Cotesia congregata•On imported cabbageworm: Cotesiaglomeratus

•On aphids: Diaeretiella rapae– Ichneumonid wasps•On diamondback: Diadegma insulare

Parasitoids• Some wasps–Braconid wasps•On hornworm: Cotesia congregata

•On imported cabbageworm: Cotesia glomeratus

•On aphids: Diaeretiella rapae

– Ichneumonid wasps•On diamondback: Diadegma insulare

–Other wasps•On whiteflies: Encarsia

•On caterpillar eggs: Trichogramma

Parasitoids• Tachinid flies–On squash bug:

Trichopoda pennipes–On striped cucumber

beetle: Celatoria setosa

adulteggs

pupaadult

Parasitoids

• Some species attack eggs **• Some species attack larvae• Some species attack pupa• Some species attack adults

** prevent the most damage

Our smartphone app!

• Name: Good Bugs +• Platforms:

–For iPhone & Android• Now free (was $2.99)• Topics:

–Natural enemies: i.d., biology, mgmt–Pollinators–Native plants that support them

& Vertebrate predators eat insects!• Bats• Toads• Birds• Geese• Hogs

Biological control by conservation of local

natural enemies: tactics

• Avoid broad-spectrum insecticides• Provide resources:–Pollen & nectar (refuge)–Spray sugar/protein mix–Winter shelter–Alternate prey (banker plants)

• Attract with lures

Insectary planting as refuge for natural enemies

• Adult parasitoids need nectar• Adult predators need pollen• Plant flowering border to

enhance biocontrol

cilantrosweet alyssum

dill

Phacelia

nasturtium

Conservation of local species• Commercial lures–Spined soldier bug–Ladybug–General

Conservation of local species

• Spray sugar/protein food source:– ‘Pred Feed’• 2.5 kg/hectare in cotton

– ‘Insect Food’ from Rincon-Vitova• 0.5 – 1 lb per gallon water

Conservation of local species• Provide diversity of habitats–Hedgerows–Windbreaks

Biological control by augmentation of local

natural enemies

• Tactics:–Buy from insectary–Collect and transfer generalists

Augmentation: Collect & transfer• What to do?–Hunt for generalist predators–Collect them–Transfer them to crop

• Who, where, when?–Ladybugs on Spirea in May–Lacewings & aphid midges on

apple leaves in early June–Damsel bugs on alfalfa, April-June

Spirea : bridal wreath

• Often infested by spirea aphid in May• Good source of ladybugs & lacewings

Banker plants for biocontrol by conservation

& augmentation

• Banker plant = a plant infested by a pest• Provide a ‘nursery’ of alternate food for

the natural enemy• Must be a very host-specific pest!• Example: hanging baskets of wheat

infested with grain aphids in greenhouse tomatoes

Guardian plantsfor augmentation bicontrol

• Used in greenhouse• Dual-purpose:–Pull pests: like an indicator plant or trap crop–Support natural enemies: like banker plants

• Benefits–Saves scouting time–Need fewer shipments from insectary

• Example: marigolds in pepper; beans in tomato; lantana in herbs

Starting augmentation biocontrol• Focus on one crop• Select natural enemy–Do before season starts–Learn biology & ecology

• Decide on protocol–Monitor pest–Use threshold to plan releases–Place orders early

• Release–Observe quality control

• Evaluation

Ratio of enemy to pest??

• 1:10 a general rule• ‘Safe balance ratio’:• 1-7 pests/enemy

• ‘Unsafe balance ratio’• 10-20 pests/enemy

Trichogramma(say: TRICK – o – gram – ma)

• Tiny wasps• Lay their eggs in pest eggs• The most widely augmented

enemy in the world

Biocontrol of European corn borer

• Egg parasitoid• Trichogramma ostriniae–New species, 1980s

• Research trials–Sweet corn: since 1991•MA, NY

–Peppers: 2002 – 2012 • VA, NY, PA, ME, MA, MD, DE

healthy

parasitized

Trichogramma ostriniaeon sweet corn

• 1st: inundative, every 2-3 days• Later: inoculative, early–Eggs glued on cards– Inoculative: One release of 30,000

wasps per acre when crop is knee-high–Place on plants or on wood stakes–Place at 1 or more sites per acre–Parasitism up to 52 days after release

• Does not overwinter in NY

Trichogramma ostriniaeon peppers

• 4 releases –1 week apart –mid July - mid August

• Number released–1st: 90,000/A –then 120,000/A

Cultural controls• Crop location• Crop rotation• Variety selection• Tillage• Mulching• Delayed planting• Trap cropping• Maintenance• Fertilizer• Irrigation

Cultural Controls

• Under-utilized tactics:–Delayed planting–Trap cropping–Combined delayed planting + trap

cropping

• Best as part of multi-tactic plan

Delayed planting

• Cucumber beetle–Problem if plant in late May–Less problem if plant in mid-June

• Squash vine borer–Same

• Bean leaf beetle–Peak populations in May, July–Fewer in June

Adjust planting date for Cabbage Maggot• Crop most susceptible if in

seedling stage when new adults are laying eggs

• Emergence of the adults: – on different calendar dates each year– but always at the same time that certain

well known plants are floweringGEN. PLANT AVG. BLOOM (Ohio)

1 yellow rocket early May2 day lilies late June3 Canada thistle early August4 New England aster early Sept.

Trap cropping• Lure pest away from main crop

to a more attractive crop• Once the pest infests trap crop:–Leave it (sacrifice)or

–Hand-pick pests from trap crop or

–Spray trap crop with insecticide

Trap cropping

• Planting time options–Same time–2 weeks early for trap crop

cash crop

perimeter trap crop

Perimeter trap crop

• Collards around cabbage• Diamondback moth

Cantaloupes surrounded by perimeter trap crop of buttercup squash

Trap cropping examples

Main crop Trap crop Target pest

cabbage collards diamondback mothcabbage kale harlequin bugcucumber hubbard squash cucumber beetlespeppers sweet corn (late) Europ. corn borerpotato eggplant Colo. potato beetle

To weed or not to weed?• Some weeds act as trap crop

–Smartweed in sweet corn for Japanese beetle

• Weeds are alternate hosts of some pests

–Remove horsenettle to control pepper maggot

–Remove curly dock to control rhubarb curculio

Tillage• Deep thorough plowing affects:

–Cutworms–Wireworms–Stalk borer (pupae)–Corn earworm (pupae)–Squash vine borer (pupae)

• Reduced tillage becoming more common (for soil conservation)

Irrigation• Affects diamondback moth– Sprinkler irrigation– 5 minutes at dusk– Daily– Disrupts flight and mating

Fertilizer

• Some pests like plants with excess nitrogen (e.g. some aphids) • Others opposite

Reflective Mulch

• repels immigrating winged aphids

Cultural control: trade-offsE.g. Straw Mulch• Benefits–Moisture retention–Weed suppression–Reduces soil splash–Reduces fungal spore dispersal

• Makes some pest problems worse–E.g. cucumber beetles, slugs

Mechanical Controls• Exclusion• Removal

Row covers

• 1o for temperature control• Also block pests

Row covers to exclude pests

• Key pests–Worms on cole crops–Beetles on beans–Leafhoppers on beans

• Disease vectors–Beetles on cucumbers

(before flowering)

Row covers to exclude pests• Install on day of planting• Remove–When first flowers appear

(cucurbits)–At final harvest (broccoli,

beans)

Row covers to exclude pests

• Lightweight– ‘Agri-bon 15’, ‘Insect Barrier’–90% light transmission

(vs 70-85% for heavier covers for frost protection)

–Sources:• Johnny’s Selected Seed: $122. (10’ x 500’)• Gardens Alive: $40. (8’ x 96’)

Row covers to exclude pests• Use with or w/o hoops

• Must be anchored tightly

Exclusion by netting

• Periodical cicada

• Birds

blueberry

grapes

Mechanical Control by Removal

• Shelter traps• Attraction traps• By beating/shaking *

• Removal by vacuum• By aspirator• Removal by hand

Removal by shelter traps

• Board trap for squash bug

• Tree bands for caterpillars

Codling moth

Gypsy mothSquash bug

Removal by shelter trapsFor squash bug:• Board or shingle • Place on ground near plant• Bugs leave plant at night,

shelter under trap• Check daily, early morning• Destroy bugs squash bug

Removal by attraction traps• Slugs• Dish of beer• Catches many slugs• Often not significant

decrease in population • Apple maggot: –One red sticky ball trap

per 100 real fruit• Japanese beetle–Place AWAY from crop

to be protected

Removal by tapping or shaking

• Into bucket or tray• By broom or snow shovel• Daily• Example: Colorado potato

beetle (adults, larvae)

Sanitation or ‘clean culture’

• Collect & destroy: –crop residue after harvest

–culled fruit

–alternate hosts

–storage & processing waste

• Plant clean nursery stock

Removal by roguing

– Pull out infested plant

– For isolated infestations only

– Example: cyclamen mite on peppers

Vacuum removal

• ‘BugVac’• Colorado potato beetle in potato• Lygus bugs in strawberries• High cost machinery• Soil compaction

Removal by aspirator• Aspirator = Mouth-operated

suction device• $8 – 14 from:–BioQuip–Forestry Suppliers–Gempler’s

• Good for flea beetles, bean leaf beetle, cucumber beetle

Flaming/burning

• Early-season control of Colorado potato beetle

• Post-harvest control of squash bug

Behavioral control• by pheromones

• By kairomones

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Behavioral control

• by pheromone mating disruption

• pheromone = chemicals emitted for communication within a species

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Mating disruption by pheromones

• Goal: control the pest population by preventing mating, thus no fertile eggs to start the next generation• In orchards 5+ acres• Two techniques: –Male confusion technique–Attract-and-kill technique

Tomato Pinworm: Mating Disruption

• Key pest in FL, CA, TX

• Best where fields are isolated or whole areas are treated

• Widely adopted since 1980’s, due to insecticide resistance

Kairomonesexample: cucurbitacin

• CideTrak D–Gustatory stimulant–Mix with insecticide

(such as Entrust)• Bait traps–Trap-out tactic

Poison bait: cucurbitacin + carbaryl (inside trap)Volatile lure: mimic squash flowers

Microbial Control

Control by micro-organisms that cause disease in insect• Bacteria• Viruses• Fungi• Protozoans• Nematodes

Micro-organisms for Insect Control

• Bacteria–B.T. = Bacillus thuringiensis•B.t. kurstaki (caterpillars) *•B.t. aizawai (caterpillars) *•B.t. tenebrionis (certain beetle larvae)•B.t. israelensis (mosquito larvae)

–Bacillus popillae (Milky Spore)

* OMRI

Micro-organisms for Insect Control

• Viruses–Cyd-X, Spod-X, Gemstar *

• Fungi–Beauveria bassiana (Mycotrol, Naturalis) *

• Protozoans–Nosema (Hopper Stopper; Nolo Bait) *

• Nematodes–Steinernema carpocapsae (Millenium)–Heterorhabditis bacteriophora (Symbion)

* OMRI

What is B.t.?• A natural soil-borne bacterium• Species: Bacillus thur in gi en sis• produces crystal-like proteins that

kill certain insects• Produced by fermentation methods• Discovered 1915; used since 1957

B.t. products• Sprayable–For caterpillars:•DiPel, XenTari, Biobit (Valent)•Javelin, Agree, CryMax, Deliver

(Certis)–For Colorado potato beetle:•Trident (Certis)

• Transgenic crops– ‘Attribute’ & ‘Performance’ sweet corn

How does B.t. work?

• B.t. must be eaten by target insect• B.t. contains toxins that are

activated by insect’s gut enzymes• toxins paralyze insect’s digestive

tract • feeding stops within 2 hours• death takes 1 - 5 days

Sprayable B.t.: performance• Sometimes erratic due to:–Breakdown in U.V. light–Reduced toxicity against older larvae– Incomplete spray coverage–Too long a spray interval

• Best if:–Target young larvae–Apply at 3-4 day intervals–Get thorough coverage •Lot of water (>35 gal/A)•Good pressure (60 psi)

Chemical control

Chemical control

• Insecticides

• Repellents

• Attractants

Do any pesticides have valid place in organic agriculture?

• Strict organic practitioners: no• Many organic practitioners:

yes, if natural origin

OMRI: The Organic Materials Review Institute

• Certified organic growers• List of products

–Fertilizers–Pesticides

• Crops & processing

Example of label with OMRI logo

Insecticide Classification

• By origin

• By mode of action

Insecticides, by Origin• Natural

– Minerals & elementals– Oils & soaps– Abrasion agents: diatomaceous earth– Botanicals (plants)– Microbials– Compounds derived from microbes

• Synthetic– Mimics of natural insect pheromones– Mimics of natural insect hormones– Petroleum-based synthetic chemicals

ok

not ok

Note on natural insecticides

• Can be toxic to natural enemies• “Natural” is not always good!

Insect control products on OMRI ListCategory Action Item

Narrow spectrum

Mating disruption (behavioral control)

pheromones

Cause illness (microbial control)

virusesbacteria

Broad spectrum

Cause illness(microbial control)

fungi

Smothering soaps, oils

Abrasion diatomaceous earth

Nerve poisons spinosad (Entrust)pyrethrins (PyGanic)

Repellency kaolin, garlic,neem / azadirachtin

Minerals & elementals

• kaolin• iron phosphate• sulfur

‘Surround’

• A.I. = kaolin (clay)• ‘Particle film technology’• Broad spectrum crop protectant• Photosynthesis not affected• Acceptable for organic production

Repellent:‘Surround’ on pumpkin

‘Surround’ on apple

Smothering or suffocation agents

• oils: – from petroleum– from plants

• insecticidal soaps:– potassium salts of fatty acids

Abrasion agent:Diatomaceous earth• Silicon dioxide = fossilized remains of algae• Disrupts water balance• For indoor pests: sold alone• For food crops: sold in mix with pyrethrins• Not rainfast

Insecticides from plants (botanicals)

• pyrethrum (chrysanthemum)• azadirachtin (neem tree)• garlic extract• [ sabadilla ]Not on OMRI list:• capsaicin (hot pepper)• nicotine (tobacco)

From the neem tree

azadirachtin(extract)

neem seed oil

pyrethrum(from chrysanthemum)

& pyrethrins(components of pyrethrum)

• Allowed for organic:• alone• + oil• + soap

pyrethrum (from chrysanthemum)

& pyrethrins(components of pyrethrum)

• Allowed for organic:• alone• + oil• + soap

• Not allowed:• + PBO= piperonyl butoxide

What’s PBO?• PBO = piperonyl butoxide• synthetic sassafras oil• A synergist• When mixed with some insecticides,

makes them more active–Most common with pyrethrins–Also used with pyrethroids, rotenone, &

carbamates• Prevents enzymes from detoxifying

the a.i. before it acts on target site

Efficacy of Pyrethrins

• Pyrethrins + PBO

–Very effective in field & lab tests

• Pyrethrins + oil

–Not effective in lab tests

• Pyrethrins + soap

–Not effective in lab tests

Microbial insecticides:cause disease in insects

• Bacteria• Viruses• Fungi• Protozoans• Nematodes

Insecticides derived from

microorganisms

• spinosad–from a soil actinomycete–discovered behind rum

factory in Carribbean

Insecticides derived from microorganisms:spinosad in ‘Entrust’

• Excellent for caterpillar control• Use 3 - 6 fl oz/acre• $403 - 489/quart!

Mimics of natural insect hormones

• Types– juvenile hormone–molting hormone–chitin biosynthesis

• Biorational• Not on OMRI list

Insect Growth Regulators (IGRs)

• Normal hormones:–Control duration of immature stages–Control when immature becomes adult

• IGRs control insects by modifying normal insect development–Block ability to change immature to adult– Force change to adult before physically

able to reproduce

Insect Growth Regulators

• Class: hormone receptor agonists– interfere with molting hormone• tebufenozide (Confirm)•methoxyfenozide (Intrepid)

– interfere with juvenile hormone• pyriproxyfen (Esteem)• neem (Azatin, Neemix)

Insect Growth Regulators

• Class: chitin biosynthesis inhibitors– Interfere with formation of exoskeleton–3 types:•Caterpillars: diflubenzuron (Dimilin)•Maggots: cyromazine (Trigard)• Leafhoppers: buprofezin (Courier)

Bioassays to test efficacy of insecticides on pests

• Basic set-up– 8 oz deli dish– Leaf sprayed both sides

• Residual tests–Pests added after residue

dry• Direct tests–Pests added before spray

Bioassay Results

• % Mortality, for all pests• Damage, for chewing pests• Importance: –#1: Prevention of damage–#2: Death of pest

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Bean leaf beetle

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Bean leaf beetle

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Potato Aphidtested on tomato leaves, 10/3/2006

3 replicates/treatment, 10 aphids/replicate

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A natural enemy: ladybug

oo

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ooo

Field trial on snap bean• Late planting (seed late August)• Heavy beetle pressure• Start sprays as soon as seedlings

emerge• Spray 10 times on 1- to 5-day schedule

– Azadirachtin– Capsaicin– Garlic– Neem seed oil– Pyrethrins– Rotenone

• Spray 5 times on 5- to 8-day schedule– Spinosad

• Spray 4 times on 7- to 10-day schedule– Carbaryl– Permethrin– Endosulfan

Field trial on snap beans(bean leaf beetle + spotted cucumber beetle)

Trends in insecticide efficacyspectrum Exc./Good Good/Fair Fair/Poor

broad pyrethrins + PBOcarbarylesfenvaleratelambda-cyhalothrincyfluthrinbifenthrin

acetamipridpermethrinmalathionpyrethrins + oilpyrethrins + soapazadirachtin

neem seed oilcapsaicingarlic

narrow spinosadsoaprotenonedicofol

B.T.oilendosulfan

in red if on OMRI list

How to use insecticides in presence of beneficial insects?

Choose product:• Selective (by mode of action)–Kills pest but not the natural enemies–Allows natural enemies to help kill pest–Example: B.t. (‘Dipel’)

or• Very short residual activity–Most botanicals

How to use insecticides in presence of beneficial insects?

• Choose placement:–Selective placement• In space• In time

–Provide refuge

‘Spot treatment’ allows refuge

• Spray border rows only, for pests that invade from one edge–Colorado potato beetle–Strawberry clipper weevil–Brown marmorated stink bug

Biobest:Webpage & mobile app on ‘side effects’for 21 natural enemies & 263 chemicals

Biobest: 4 predators & 5 OMRI products

similar trends on chart by Koppert

Trends?• Not harsh:–azadirachtin–B.T.

• Harsh:–soap (potassium salts of fatty acids)

• Mixed results:–spinosad–pyrethrins–mineral oil

Hierarchy of harshness to natural enemies

Spray conventional (non-OMRI) >>

Spray OMRI broad spectrum (soaps, oils, botanicals, fungi) >>

Spray OMRI narrow spectrum (viruses, pheromones, bacteria) >>

No spray

Costs of using chemicals for pest management?• Input $ costs–Materials–Labor

• Environmental costs

EIQ=Environmental Impact Quotient

• Developed at Cornell:–Joe Kovach et al. 1992–Website remains active

• www.nysipm.cornell.edu/publications/eiq/

EIQ: Allows comparisons• Basic EIQ value per chemical–Based on 14 effects: toxicity, leaching, etc.

• ‘Field use EIQ calculator’– Input name & % of active ingredient– Input application rate–Output: 1 number

• Small number = low impact (good)• Large number = high impact (bad)

EIQ examplesEntrust SC, 3 fl oz/A

Wettablesulfur, 12 lb/A

Javelin (B.t.), 1 lb/A

Field use EIQ

0.6 361 11.3

Consumer 0.1 92 2.1Worker 0.3 241 5.9Ecological 1.5 749 26.0

EIQ example: apples

Product Rate Field use EIQ

Imidan 70W 3 lb/A 69Pyganic 5EC 12 fl oz/A 1.4Entrust SC 7 fl oz/A 1.4Aza-Direct 24 fl oz/A 0.2Surround WP 25 lbs/A 190Wettable sulfur 12 lbs/A 361

EIQ example: sweet cornProduct Application

RateField use EIQ

Lannate LV 1.5 pt/A 9.6Warrior II 1.92 fl oz/A 1.2Coragen 3.5 fl oz/A 0.7Entrust SC 3 fl oz/A 0.6

Examples of organic tactics

• Cole crops• Cantaloupes & squash• Sweet corn

3 cabbage caterpillars & their parasitoids

Imported cabbageworm

Cabbage looper

Diamondback moth

Diadegma insulareoviposits on larvae

Cotesia larvae spinning cocoons

Cotesiaadult wasp

Copidosoma floridanum wasps emerging from one cocoon

Parasitoids of Diamondback:Ohio surveys 2011-2012

from Emily Linkous

Diadegma insulare, Parasitoidof Diamondback Moth Larvae

Adult wasp

Photo by Andrei Sourakov

Diamond-back

larvae

Diadegma insulare, Parasitoidof Diamondback Moth Larvae

• small wasp, 1/4” long• black body, red/brown marks• adult wasp lays egg in older caterpillar• new adult wasp emerges from pupa

Diamondback pupae

Healthypupa

Parasitizedpupae

Photo by J. Ogrodnick

Biocontrol of diamondback moth by Diadegma insulare in Ohio

• % of diamondback larvae attacked (Ohio 2011-2012):– 48% in plots without insecticide– 33% in plots with insecticide– 28% in commercial fields

Insecticide Imported cabbage-worm

Diamond-back moth

Cabbage looper

Natural enemies

Conventional Excellent control

Fair control

Good control

Poor survival

B.t. Good control

Good control

Fair control

Excellent survival

Caterpillar management on cole crops

Thus B.t. works best when diamondback moth or imported cabbageworm is dominant pest

Integration of microbial control & biocontrol of caterpillars on cole crops

• Plant border of sweet alyssum to attract parasitoids• Use the microbial insecticide BT as a

selective insecticide– ‘DiPel’, ‘Xentari’, etc.–Kills caterpillars–Does not kill parasitoids–Allows natural enemies to help kill pests

• Spinosad also easy on parasitoids

Choose Cabbage Variety to Avoid ThripsLess damage More damageBravo AzanFresco AtriaCheers ColeguardTitanic90 MegatonKingCole UptonSuperkraut Hinova

KrautpackerRodolphoSuperdane

Data on >80 varietiesTrials 1987-1999C.Hoy, K.Scaife, M.Kleinhenz

Adjust Cover Crops for Thrips• Used to protect soil over winter• Affects onion thrips–Overwinters in small grains–Does best in wheat–Does poorly in rye

Adjust planting date for Cabbage Maggot• Crop most susceptible if in

seedling stage when new adults are laying eggs

• Emergence of the adults: – on different calendar dates each year– but always at the same time that certain

well known plants are floweringGEN. PLANT AVG. BLOOM (Ohio)

1 yellow rocket early May2 day lilies late June3 Canada thistle early August4 New England aster early Sept.

Adjust irrigation timing for

caterpillars

• Sprinkler irrigation affects diamondback moth (adult)

– 5 minutes at dusk– Daily– Disrupts flight and mating

Integrated Methods for Cole CropsCultural Biological Chemical

• Caterpillars

• Thrips

• Flea beetles

• Aphids

• Root maggots

Cucumber beetles

Damage:

• Chew seedlings

• Chew on fruit surface

• Transmit bacterial wilt

Row covers: from transplant until first female flowers

(removal, July 19th)

‘Surround’ (kaolin)applied to cantaloupe after

row covers removed

CideTrak D• Gustatory stimulant• Buffalo gourd root powder• Cucurbitacin• Not insecticide• Mix with insecticide• 3.1 oz/A• On OMRI list (as adjuvant)• Costs $92.50 for 4-lb bag

Cantaloupes surrounded by perimeter trap crop of buttercup squash

Summary:Cucumber beetle management

• Biological–Conserve parasitoid flies

• Cultural:–Plant late (mid-June)–Perimeter trap crop

• Mechanical:–Row covers–Mass trapping

• Chemical–Surround–CideTrak D + Entrust

Corn earworm in sweet corn

• Source: moths migrate from Southern USA• Egg laying site: on silks• Egg hatch time: 2-3 days

Organic Alternative for Worms in Sweet corn: B.t. + Oil

(Ruth Hazzard, Univ. Mass.)

• ‘Zea-later II’ applicator– Hand-held– $99 (Johnny’s Selected Seeds)

• Mix:– 900 ml food-grade corn oil– Lecithin 5% (emulsifier)– 28.6 grams DiPel DF (a B.t.)– 100 ml water

• Treat:– Once, 5 days after silking begins– Squirt 0.5 ml of oil mix into each ear tip

Organic management tactics

Summary:• Many tactics available• Non-chemical:–Must be emphasized–Knowledge & labor intensive

• Chemical:–Usually as last resort–Choose least disruptive product–Beware efficacy fair to poor

Info on vegetable & fruit insect pest management

u.osu.edu/pestmanagement/

Questions?e-mail: welty.1@osu.edu

phone: 614-292-2803

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