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11/30/2010
1
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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