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Vegetable Garden Pests

MGV Specialty Training 2010Sharon Morrisey

Consumer Horticulture AgentMilwaukee County UW-Extension

So who are we talkin’ about?• Insects

• Diseases

• Entomology – Program Manual - Unit 5 incldg. p.

25– Pubs. – “Managing Insects in the

Home Vegetable Garden”– Wisc. Garden Facts

• Plant Pathology

• Weeds

• Wildlife

– Program Manual – Unit 6– Pubs.– Wisc. Garden Facts

• Weed Science– Program Manual – Unit 7A

• Wildlife Management– Program Manual – Unit 12A– Pubs. – Rabbits, Ground

Squirrels, Raccoons, Deer

Approaches to managing pests

• Integrated Pest Management (Unit 7B)

“A decision-making tool that utilizes cultural, physical, biological and chemical PMphysical, biological and chemical PM

strategies to prevent economically-damaging pest outbreaaks while reducing the risks to

human health and the environment”.

• Integrated Pest Management Concepts

Key pestsGeneralistsSpecialistsOpportunistic pests

MonitoringVisual

Proper identificationBiology of the pest

Kind of damageDamaging stageTiming

Tolerance levelsThe plantVisual

observationTrapsSweep netsExtraction

The plantYou Economic thresholds

• Integrated Pest Management Control Methods

To reduce numbers not eliminate• Cultural

• Physical/ Mechanical• Physical/ Mechanical

• Biological

• Chemical

• Cultural Controls• Prevention through good cultural care

– Match plant to site» Use natives that are adapted to soil, climate, etc.

– Select disease resistant varieties– Purchase healthy, disease and insect-free plants– Rotate crops

» to prevent carry-over of disease and insectsp y– Control weeds before planting new plants/ gardens– Properly space plants

» To reduce competition for light, nutrients and water» To allow air circulation to dry leaves and prevent

diseases– Properly water and fertilize

» Vigorously growing plants outcompete weeds, resist diseases and insects

» Avoid overhead watering

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• Prevention through good cultural care (cont’d)– Mulch

» to maintain moisture» to prevent weed growth

– Modify the environment» Orient rows north-south» best light exposure» good air circulation to dry leaves and prevent

diseasesdiseases– Control insect vectors of diseases

– NOT Companion planting» Equivalent of a trap crop in agricultural systems

• Physical Controls• Sanitation

– Remove infested/ infected plant debris throughout the season» Plant parts» Whole plants

– Remove, burn or bury (till-in) infested/ infected plant debris at the end of the season

– Don’t work among wet foliage– Smokers should wash hands after smoking– Disinfest tools & equipment (Lysol, rubbing alcohol, bleach)

• Pick off and remove insects• Traps to attract, collect and remove insects• Pull, hoe, or cultivate weeds• Barriers

– floating row cover as a barrier– Tin cans or cups as collars around transplant stems– Tin foil around lower stems of squash

• Biological Controls• Beneficial Organisms

– Predators – feed on pest organisms– Parasitoids – develop within the pests body– Pathogens – disease-causing organisms that kill or debilitate the

pest– Concepts

» Conservation» limit or eliminate pesticide use» maintain or provide habitat needed» host plants, nectar sources, cover» Augmentation» to increase existing populations» Importation» bring in beneficials not already present» usually non-native beneficials for non-native pests

– Problems» Lag time» Proper timing for release» Mixed crops and pesticide use

– Common beneficials:» Lady beetles» Green lacewings» Wasp parasitoids» Nematodes (entomopathogenic)» Nematodes (entomopathogenic)» Bacillus thurengiensis» Var. kurstaki - caterpillars» var. tenebrionis – certain leaf feeders – Colorado potato beetle» var. israelensis – mosquito and black flies

• Chemical Controls• Pesticides

– Insecticides kill insects– Fungicides kill fungi– Herbicides kill plants

(weeds,preferrably)

– Miticides kill mitesMiticides kill mites– Nematacides kill

nematodes– Rodenticides kill rodents– Molluscicides kill snails

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• Chemical Controls• Pesticides

– Botanical insecticides (Organic)» Neem (azadirachatin) – from neem tree» Pyrethrins (pyrethrum) – from chrysanthemums» Rotenone – from derris root; Parkinson’s (?)» Spinosad – from a soil-borne fungus

– Insecticidal Oils (Organic)» Dormant» Summer» Plant extract – citrus, clove, garlic, capsaicin

– Insecticidal soap (Organic)

– Inorganic insecticides (mostly organic)» Cryolite (sodium fluoaluminate)» Diatomaceous earth (fossil shells of microscopic

marine algae called diatoms.» Kaolin » Sulfur» Bordeaux (lime and copper sulfate)» Lime sulfur» Baking soda» 1 ½ T. baking soda + 3 T. horticultural oil in 1 gallon of water

– Synthetic insecticides» Toxicities – signal words» Caution – least toxic» Warning» Danger – Poison – most toxic» Formulations» Dry – dusts, granules, wetable powders» Liquid – emulsifiable concentrates, flowable» Liquid emulsifiable concentrates, flowable» Baits» RTU (Ready To Use)

– Common synthetic insecticides» Carbaryl (Sevin)» Halofenozide (Grub-Ex)» Imidocloprid (Marathon)» Isotox» Malathion» Methiocarb (Mesurol)» Methoxychlor» Methoxychlor» Phosmet (Imidan)» Pyrethroids (bifenthrin, cyfluthrin, deltamethrin,

esfenvalerate, lamba-cyhalothrin, permethrin)» Tricholorfon (Dylox, Proxol)

– Fungicides» Protectant» Systemic

– Herbicides» Non-selective/ total vegetation killers» Selective» pre-emergent» pre emergent» post-emergent

Overview of Insects• Only 1% of the 87,000 spp. in US & Canada are pests!!!• Arthropods

• millipedes, crayfish• Class: Arachnida - spiders, ticks, mites• Class: Insecta

– 3 body regions – head, thorax, abdomen– 3 pairs legs on thorax– 1 pair antennae– Wings – Compound eyes– Exoskeleton

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• Metamorphosis – change in form– Gradual (simple or incomplete)

• Egg, nymph, adult– Grasshoppers, aphids, true bugs, leafhoppers, cockroaches

– Complete• Egg, worm-like larva (pl. larvae), pupa (pl. pupae),

adult

• Orders –– 26 -30 based on types of:– Metamorphosis, mouthparts, wings.

• Types of injury– Chewing

• Chewing mouthparts (beetles, caterpillars, maggots)– Defoliation, skeletonizing, leafmining, girdling

• Sucking mouthparts (aphids, plant bugs, many beneficials)

– Deformed plant parts, speckling, stunting, yellowing, wilting– Transmission of plant diseases– Transmission of plant diseases

• Rasping (thrips, mites)– Stippling

– Galls

Overview of Diseases• Disease Triangle

– Susceptible host– Disease-causing organism– Favorable environment

• Control focused on modifying any of these

• Causes of Disease– Abiotic – no organism– Biotic

• Fungi• Bacteria• Viruses• Phytoplasmas• Phytoplasmas

• Signs – physical evidence of the pathogen– Fungal hyphae, fruiting bodies, spores, bacterial ooze

• Powdery mildews – hyphae & spores• Rust – pustules of spores (fruiting bodies)

• Symptoms – plant’s expression of disease– Necrosis

• spots, lesions, blights, cankers, rots, damping-off– OverdevelopmentOverdevelopment

• galls, warts, brooming– Underdevelopment

• stunting, distortion, – Discoloration

• yellowing or chlorosis, reddening or marooning, mosaic, ringspots, mottle, virescence.

– Wilting – vascular wilts

Overview of Weeds• Plant type

– Grass– Broad-leaf

• Life cycle– Annual

• Summer• Winter

– Biennial– Perennial

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• Reproduction– Seeds– Plant parts – roots

• DispersionWind– Wind

– Water– Animals– Humans

• Control– Mechanical

• Cultivation• Hoeing (Santa Claus)• Pulling

– Mulching• Prevents germination• Smothers • Burns (clear plastic)

– Herbicides

• Control– Strategies without herbicides

• Seeds– Prevent seed production & distribution– Exhaust seed bank – till, grow, till, grow– Block light to seed

» Cover - mulch» Bury – deep tillBury deep till

– Cut-off seed heads• Annuals

– Prevent seed production– Physically remove – Smother

• Perennials with extensive roots– Pulling or tilling may WORSEN it– Smother– Starvation –

» Cut-off repeatedly without much regrowth» Exhausts root system

• Control – Herbicides

• Pre-emergent– Apply to soil– Water in– Can mulch over but don’t cultivate

• Post-emergent– Timing– Non-selective– Selective

» DCPA (Dacthal)» Pre-emergent – apply and water in» Annual grasses (some broadleaves)» Trifluralin (Treflan or Preen)» Pre-emergent – apply and incorporate» Annual grasses (some broadleaves)

– Phenoxy herbicides (2,4-D)– Post-emergent– Broadleaves– Drifts easily– VOLATILE– amine formulation is less (vs. ester)– especially above 80 –– Dedicated sprayer p y

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• Common weeds– Annuals

• Grasses– Crabgrass– Foxtails

• Common weeds– Annuals

• Broadleaves– Chickweed – Lambsquarters – Pigweed – Purslane

• Common weeds– Perennials

• Grasses– Quackgrass

• Broadleaves– Dandelion – Creeping charlie

Overview of Wildlife• Best strategy is combination of methods

– Exclusion– Removal– Repellentsp– Scare tactics– Habitat modification– Cultural changes– Increased tolerance

• Vegetable garden pests– Rabbits– 13-lined ground squirrels– Eastern chipmunks – Raccoons– Deer

• Rabbits– Brushy fencerows,

brush piles– Carrots, peas,

beans, beets– Control:

• Predators – even catscats

• Habitat destruction• Traps – relocate 20

mi.• Exclusion – 1” or

less mesh; 2’ tall; tight to ground

• Repellents – area/ smell; rotten eggs

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• 13-lined ground squirrels– Carries tail straight out behind– Hibernates – Eats seeds of vegetables – peas, cucumbers, squash, melons,

corn– Predators – hawks, snakes, other mammals– Control:

• Exclusion – ½ ” hole fencing• Habitat – allow grassy areas to grow

L th l i t fl di t fl h t• Lethal – poisons, traps, flooding to flush out

• Eastern chipmunks– Carries tail upright; lines around eyes– Dig up plants in containers, feed on plants, pull up bulbs, tunnel

in rock walls– Control:

• Exclusion – ¼” wire mesh, caulking• Habitat – eliminate bird seed, wood piles• Lethal – trapping

• Raccoons– Related to pandas– Front feet resemble humans’– Omnivores – nuts, fruits, berries, seeds, insects, fish,

frogs, eggs, birds, mammals, crayfish, carrion, garbage

– Do not hibernateNocturnal– Nocturnal

– Can carry rabies and other diseases– Control:

• Remove food source• Trap to relocate (10 mi. or more) or destroy• In sweet corn, electric wire at 8”, dog, radio under a can, plant

prickly plants like squash

• Deer Major Pests of Vegetable Crops

• Leafy vegetables• Root crops• Cole crops• Legumes• Legumes• Cucurbits• Solanaceous crops• Sweet Corn

Generalists: Insects• Cutworms

– Larvae of night moth– Flies north in May and

June– Feeds on seedlings

• Just below groundg• Just above ground• On leaves (Varietated

Cutworm)

– Control:• Collars 1 ½ “ into

soil

Generalists: Insects• Slugs

– Feed on fruit near ground

– Feed on cole crops• Leaves and stems

– Control• Remove mulch • Hand pick• Iron phosphate

(Sluggo)

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Generalists: Insects• Aphids

– Host specific– Many colors– Reproduce in 3 – 5

days in warm weatherCurled into leaves– Curled into leaves

– Control:• Blast of water• Insecticidal soap• Malathion

Generalists: Insects• Flea beetles

– Tiny, shiny black beetles

– Hop like fleas when disturbed

– OW in gardenO ga de• Adults very early

– Attracted to mustard oil

– Control:• Row cover immediately• Carbaryl• Spinosad

Generalists: Insects• Japanese beetles

– Metallic beetle with 6 white dots along sides

– Chew between veins– 400 host plants– Control:Control:

• Traps at neighbors• Hand pick into soapy

water• Pesticides

– Carbaryl– Spinosad

Generalists: Insects• White grubs

– New gardens from turf only

– Larvae of May/June beetle

– Chew plant rootsp– Control:

• Till to expose spring and fall

• Granular diazinonbefore planting

Generalists: Diseases• Root rot

– Several organisms– Wet soil that doesn’t

dry out– Control:

• Stop wateringStop watering• Remove mulch• Pre-plant add o.m.• Avoid spreading soil• Protectant fungicides

Generalists: Diseases• Herbicide injury

– Mostly from 2,4-D types

– Symptoms:• CuppingCupping• Leathery• Strapping• Adventitous roots

– Control:• prevention

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Major Pests of Perennial Vegetables

• Asparagus– Asparagus Beetles

• Larvae and adults feed• Eggs like razor stubble• Control:Control:

– Hand pick/ rub off eggs

– Remove foliage in fall– Pesticides

» Carbaryl» Rotenone » Spinosad/

Neem?

Major Pests of Perennial Vegetables

• Rhubarb– None major

Major Pests of Leafy Vegetables

– Spinach leaf miner• Spinach, Swiss

chard, Beets• Small flies• Larvae inside leaf• Larvae inside leaf• Tan blotches with

“pepper” inside• Control:

– Remove infested leaves and destroy

Major Pests of Leafy Vegetables

– Flea beetles• Arugula• Mustard greens

Major Pests of Root Crops

• Onions– Onion maggots

• Whitish maggot of a gray fly

• Control:– Rotate out of onion

crops for a while– Onion thrips

• Barely visible, cigar-shaped insects

• Inside axils and growing points

• Rasping feeding• Control:

– Can be tolerated

Major Pests of Root Crops

• Potato Insects– Potato leafhopper

• Blown into state• 1/8” wedge-shaped• Fly off when disturbed• Toxic saliva causes “hopper

burn”bu• Control:

– no cultural controls– Pesticides

» Carbaryl or malathion

– Colorado potato beetles• Adults and larvae feed on

new growth for several weeks• OW as adults• Control:

– Hand-pick– spinosad

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Major Pests of Root Crops

• Potato Diseases– Early blight

• Spores travel on wind• Lesions on lower leaves

first• Leaves only

Early Blight

• Leaves only• Control:

– Rotation– Remove infested debris– Nitrogen fertility– Avoid excess watering

Major Pests of Root Crops

• Potato Diseases– Late blight

• Spores travel on wind• Cool nights, warm days,

high humidity favors• Leaves and stems• Leaves and stems• Control:

– Rotation – Destroy infested

debris– Protectant

fungicides» Copper

(organic)» chlorothalonil

Major Pests of Root Crops

• Carrots– Aster yellows

• Vectored by leafhoppers that blow into state in May and June

• Stunting, yellowing, g y gdistorted growth

• Control:– Select resistant varieties

» ‘Scarlet Nantes’» ‘Gold King’

– Control leafhoppers– Remove and destroy

infected plants

Major Pests of Root Crops

• Beets– Leafminer– Mice

Major Pests of Cole Crops

• Flea beetles• Caterpillars

– Diamondback moth– Imported cabbage worm

C bb l

Diamondback

– Cabbage looper– Control:

• Exclusion – row cover• Biological – B.t.

Imported

Looper

Major Pests of Legumes

• Leafhoppers • Seed corn maggot

– White maggot of a small gray fly

– OW as pupa in soilC l d th– Cool, damp weather

– Cool, high o.m. soil– 5 generations

• Worst in May & June– Poor germination and

emergence or leafless stems

– Control:• Yellow pans of water to catch

adults• Plant into warmer, drier soil

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Major Pests of Legumes

• Japanese beetles• Bean leaf beetle

– Adults o.w. in weeds and emerge in mid-may to June

– Lay eggs in soil near stems– Larvae chew roots, nodules &

stems for 30 daysy– Adults in mid-July

• chew holes in leaves from underneath

– Adults in Aug. and Sept.• Chew on seed pods

– Control:• Control weedy areas• Plant early to avoid adults• Row cover at planting• Pesticides

– Neem, pyrethrum, rotonone, spinosad(?)

– Carbaryl or permethrin

Major Pests of Cucurbits

• Insects– Squash vine borer

• Adults lay eggs late June

• Larvae tunnel into stem• Plants wilt• Plants wilt• Control:

– Wrap lower stem– Hand pick eggs– Slit stem and remove

larvae» Bury cut portion

– Inject stem with B.t. (?)

Major Pests of Cucurbits

• Insects– Squash bug

• Mid to late season• Piercing and

sucking mouthparts• Control

– Remove eggs– Hand pick nymphs

and adults– Soapy water– Pesticide:

» carbaryl

Major Pests of Cucurbits• Insects

– Cucumber beetle• Adults start feeding as

soon as cotyledons emerge

• Chew leaves, flowers and fruitand fruit

• Transmit bacterial wilt disease

• Control:– Hand pick adults

» thoroughly– Pesticides

immediately» Carbaryl» Rotenone» Neem

Major Pests of Cucurbits

• Diseases– Bacterial wilt

• Transmitted by cucumber beetlesL ilt th• Leaves wilt then perk up, wilt then perk up, then wilt

• Cut stem with ooze• Control:

– Control cucumber beetles

– Remove & destroy

Major Pests of Cucurbits

• Diseases– Powdery mildew

• temperatures are between 68-81°F,

• relative humidity is high,

Powdery Mildew

• free water is low, • light intensity is low• Late season

– Downy mildew• Cloudy, overcast skies• High humidity (>6 hrs

100% RH)• Foggy mornings• Air temperatures 59-77oF

Downy Mildew

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Major Pests of Cucurbits

– Controls:• Select resistant

varieties• Properly space

Powdery Mildew

• Properly space• Avoid overhead

watering• Pesticides:

– PM – baking soda & oil

– DM – chlorothalonil or copper

Downy Mildew

Major Pests of Solanaceous Crops

• Tomato Insects– Hornworm

Major Pests of Solanaceous Crops

• Tomato Insects– Whiteflies

Major Pests of Solanaceous Crops

• Tomato Diseases– Fusarium– Verticillium– Black walnut

toxicity

Major Pests of Solanaceous Crops

• Tomato Diseases– Early blight– Septoria– Late blight

Early Blight

g

SeptoriaLate Blight

Major Pests of Solanaceous Crops

• Tomato Disorders– Blossom end rot

• Poor distribution of calcium

• Due to uneven moisture• Adding calcium doesn’t

help• Control:

– Even watering– Mulch soil– Avoid root damage– Select resistant

varieties

Blossom end rot of tomato.

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Major Pests of Solanaceous Crops

• Tomato Disorders– Cracking

• Change in growth rate

C f i– Catfacing• Cold temperatures

during fruit set– Sunburning

• Insufficient foliage

Major Pests of Solanaceous Crops

• Tomato Disorders– Physiological leaf

roll• Caused by stress

Major Pests of Solanaceous Crops

• Tomato Disorders– Herbicide toxicity

Major Pests of Sweet Corn

• Insects– Seed corn maggot

– Corn earworm• Both caterpillars• Cut off ear tip

before cooking

Major Pests of Sweet Corn

• Diseases– Smut

• Fungus• Select resistant

i tivarieties• Develop a taste for

it

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