Common Vegetable Garden Insect Pests -- Harvest to Table

Vegetable garden insect pests are susceptible to many controls. Limit insect damage by identifying pests quickly and recognizing the damage they inflict. Regular visits to the garden will help you spot pests before they become established. Then choose the most effective control given the infestation. The quickest controls for light infestations are listed below under “Prevention and controls.” The “natural insecticides” listed here are the last line of defense; natural insecticides can harm beneficial insects if not used carefully. Encourage beneficial insects–listed under “biological controls.”

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Here are common vegetable insect pests:

Aphid

Scientific name: Order Homoptera: Family Aphididae
Description: Tiny soft-bodied, pear-shaped insects may be pale green, brown, yellow, pink, blue, or black. Usually wingless but some females may be winged. Adults less than 1/10-inch long.
Emergence time: Eggs over-winter hatch in early spring, throughout the growing season.
Susceptible plants. Nearly all vegetables, fruits, and many other plants.
Damage: Sucks sap from leaves, fruits, stems causing foliage to curl, pucker, and yellow; loss of plant vigor; some transmits diseases such as mosaic; excrement supports black, sooty mold; attracts ants
Prevention and controls: Spray away with strong water; soapy water spray; aluminum foil placed on the ground under young plants reflects the sky and confuses insets; as a lure, use yellow containers of soapy water, commercial yellow stick traps, or a board painted yellows and coated with a sticky solution such as Tanglefoot; cover plant with Spun polyester blanket or other row covers.
Biological controls: Ladybugs; spiders; syrphid flies; lacewings.
Natural insecticides: Insecticidal soap; nicotine. Pyrethrum; sabadilla; use with care, insecticides also kill beneficial insects. Light horticultural oil spray.
Plant companions: Plant aster and parsley family plants also alyssum or clover to attract aphid-easting beneficial insects. Onions and garlic may repel aphids. Trap crops: early cabbage, marigolds, and nasturtiums.
See Aphid Organic Pest Control.

Asparagus beetle

Scientific name: Crioceris asparagi
Description: Blue-black with four white spots and red margins; oblong to ¼ inch long.
Emergence time: Over-winter in the garden, emerge in spring.
Susceptible plants: Asparagus
Damage: Chews leaves and spear tips.
Prevention and controls: Remove plants and debris after harvest; shake beetles from foliage into soapy water; use row covers as a barrier early in the season; use rock phosphate or bone meal dust on plants.
Biological controls: Ladybugs, predatory flies.
Natural insecticides: Pyrethrum, and rotenone dust for serious problems; use with care, insecticides also kill beneficial insects.
Plant companions: Beetles dislike tomatoes, nasturtiums, and calendula.
See Asparagus Beetle Organic Pest Control.

Blister beetle

Scientific name: Family Melodae
Description: Slender, elongated metallic blue-gray, black, or black and yellow striped insect about ¾ inch long, with long legs and narrow neck. Soil-dwelling larvae do not eat vegetables.
Emergence time: Over-winter in the garden; adults emerge in early to mid-summer.
Susceptible plants: Adults feed on leaves, blossoms, and fruit of nearly all vegetables—beans, beets, melons, peas, potatoes, and tomatoes.
Damage: Chews leaves, flowers, and fruits.
Prevention and controls: Remove plants and debris after harvest; handpick or shake beetles from foliage into soapy water (always wear gloves because they secrete harmful oil that can blister the skin; use row covers as barrier early in the season; spray with canola oil; use rock phosphate or bone meal dust on plants.
Biological controls: Ladybugs, predatory flies.
Natural insecticides: Pyrethrum, and rotenone dust for serious problems; use with care, insecticides also kill beneficial insects.
Plant companions. Beetles dislike nasturtiums and calendula.

Cabbage looper

Scientific name: Trichoplusia ni
Description: Light green caterpillar with yellow stripes running down back; loops as it walks. The adult is a brownish night-flying moth with a sliver spot in the mid-forewing.
Emergence time: Spring.
Susceptible plants: Brussels sprouts, cabbage, cauliflower, Chinese cabbage, collard plants, greens, beans, peas, potatoes, and tomatoes.
Damage: Small to large holes eaten in leaves. Eats seedlings.
Prevention and controls: Dust looper-worms with flour or salt; cover plants with spun polyester blanket or other row covers to prevent moths from laying eggs; plant resistant varieties, time planting to avoid insect growth cycle.
Biological controls: Trichogramma wasps, lacewing, ladybug; Bacillus thuringiensis spray every 2 weeks.
Natural insecticides: Rotenone; pyrethrum-diatomaceous earth blend; sabadilla; use with care, insecticides also kill beneficial insects.
Plant companions: Celery is a trap crop. Intercrop with marigolds. Repelled by garlic, hot peppers, hyssop, onions, rosemary, sage, tansy, and thyme.
See Cabbage Looper Organic Pest Control.

Cabbage maggot

Scientific name: Delia radicum
Description: Small, gray-white, legless worm to ⅓-inch long, blunt end. The adult looks like a housefly.
Emergence time: Early spring to fall, several generations.
Susceptible plants: Brussels sprouts, cabbage, cauliflower, Chinese cabbage, collards, parsnips, radishes, and turnips.
Damage: Brown tunnels into stems just below the soil, and seedlings wilt and die.
Prevention and controls: Apply lime or wood ashes around the base of plants; time planting to avoid insect growth cycle.
Biological controls: Beneficial nematodes, chalcid wasps, Trichogramma wasps.
Natural insecticides: Lime-water mix drench: 2 pounds of lime per 5 gallons of water.
Plant companions: Radishes and turnips as trap crops. Mint, rosemary, sage, and tomatoes repel cabbage maggot.

Carrots with rust fly damage — Damage to carrots is caused by the larva of the carrot fly.

Carrot rust fly

Scientific name: Psila rosae
Description: Black fly to 1/5-inch long with yellow head and legs. Maggots are yellow to white about ⅓ inch long.
Emergence time: Spring, over-winter as maggots.
Susceptible plants: Carrots, celery, parsley, parsnips.
Damage: Maggots tunnel into roots causing stunting of plants; soft rot.
Prevention and controls: Sprinkle wood ashes around the crown of the plant; cultivate in winter to expose maggots; rotate crops; time planting to avoid insect growth cycle, carrots come to harvest in fall.
Biological controls: Parasitic nematodes.
• Natural insecticides: Use with care, insecticides also kill beneficial insects.
Plant companions: Onions and leeks repel fly, Also pennyroyal, rosemary, salsify, sage, and wormwood.

Colorado potato beetle

Scientific name:Leptinotarsa decemlineata
Description: Yellow convex beetle to ⅓-inch long with black stripes and orange head covering. Grubs are red with black spots and a black head.
Emergence time: Spring.
Susceptible plants: Potatoes, tomatoes, eggplants, peppers.
Damage: Skeletonized leaves, growth tips chewed.
Prevention and controls: Handpick beetles and larvae; remove orange egg masses from undersides of leaves; spray with a mixture of basil leaves and water; place a 1-inch thick layer of clean hay or straw mulch around plants to keep beetles from climbing to the stems; cover plants with spun polyester blanket or other row covers; plant resistant varieties; time planting to avoid insect growth cycle.
Biological controls: Ladybugs, Bacillus thuringiensis
Natural insecticides: Rotenone; sabadilla; use with care, insecticides also kill beneficial insects.
Plant companions: Interplant with catnip, coriander, and tansy; intercrop with basil.
See Colorado Potato Beetle Organic Pest Control.

Corn earworm / Tomato fruitworm

Scientific name: Helicoverpa zea
Description: Spiny caterpillar, white, green, or red to 1½-inches long. The adult is a brown moth.
Emergence time: Late spring.
Susceptible plants: Corn
Damage: Feed buds and leaves and later on silks and kernels at the tip of an ear.
Prevention and controls: Hand pick from husk after silks brown. When silks tassels brown, apply 10-20 drops of mineral oil with an eye dropper to the tassels or spray mineral oil on the tassels. Remove debris from the garden in the fall and cultivate thoroughly.
Biological controls: Trichogramma wasps, Bacillus thuringiensis, beneficial nematodes.
Natural insecticides: Spray young plants with horticultural oil mixed with Bacillus thuringiensis every 2 weeks. Rotenone; use with care, insecticides also kill beneficial insects.
Plant companions: Plant smartweed as a trap crop.
See Corn Earworm Organic Pest Control.

Cucumber beetle, spotted and striped

Scientific name: Diabrotica undecimpunctata howardi (spotted cucumber beetle); Acalymma vittatum (striped cucumber beetle)
Description: Yellow beetle with black head and three wide black stripes or spots on the wing covers; beetle to ¼-inch long. Larvae: slender, white grubs.
Emergence time: Adults emerge in late spring.
Susceptible plants: Cucumbers and other vine plants; beans, corn, peas, and flowers of many plants. Damage. Larvae feed on roots and stems; adults chew on leaves and shots; can transmit wilt and mosaic virus.
Damage: Chew stems, flowers, leaves, and fruit; they usually cluster around the crowns of young plants and among blossoms. Adult striped cucumber beetles spread bacterial wilt that causes vine death.
Prevention and controls: Handpick; mulch around plants; cover plants with spun polyester blanket or other row covers; plant resistant varieties; dust with wood ashes or rock phosphate; grow plants on trellises; time planting to avoid insect growth cycle. Place thick mulch around plants.
Biological controls: Braconid wasps, tachinid flies, beneficial nematodes.
Natural insecticides: Apply garlic spray. Liquid rotenone or pyrethrum; sabadilla; use with care, insecticides also kill beneficial insects.
Plant companions: Interplant with catnip, tansy, or radishes.
See Cucumber Beetle Organic Pest Control.

Cutworm

Scientific name: Order Lepidoptera: Family Noctuidae
Description: Dull gray to brown caterpillar, plump to 2 inches long, curls when disturbed.
Emergence time: Early spring; repeat generations through the growing season.
Susceptible plants: Beans, broccoli, Brussels sprouts, cabbage, cauliflower, Chinese cabbage, collards, corn, eggplants, kohlrabi, lettuce, radishes, rutabagas, peppers, potatoes, tomatoes, turnips,
Damage: Chew through plant stems just below the soil line; eat roots, leaves, buds, and fruits.
Prevention and controls: Place a 3-inch collar of newspaper or plastic around the stem when transplanting into the garden; clear the garden of weeds, grass, and plant debris in the fall to discourage egg-laying; sprinkle wood ashes around the base of plants.
Biological controls: Braconid wasps; tachinid flies; beneficial nematodes, Bacillus thuringiensis.
Natural insecticides: Diatomaceous earth.
Plant companions: None.
See Cutworm Organic Pest Control.

Earwig

Scientific name: Forficula auricularia
Description: Elongated to 3/4 inch reddish-brown, leathery forewings, pincers on the tips of the abdomen. Hide during the day and feed at night.
Emergence time: Late spring.
Susceptible plants: Many garden flowers and vegetables.
Damage: Feed leaves, flower petals, and soft fruit; leave ragged holes. Only a pest in large numbers.
Prevention and controls: Rolled wet newspaper or cardboard as traps.
Biological controls: Tachinid fly.
Natural insecticides: Spray young plants with natural pyrethrin insecticides; use with care, insecticides also kill beneficial insects. Trap in a low-side can with half an inch of vegetable oil.
Plant companions: None.
See Earwing Organic Pest Control.

European corn borer

Scientific name: Ostrinia nubilalis
Description: Gray to pink-flesh colored caterpillar with a dark head and small brown spots on each segment to 1-inch long. The adult moth has a zigzag pattern on its wings.
Emergence time: Caterpillars in spring, and moths in early summer.
Susceptible plants: Corn, chard, peppers, potatoes, tomatoes.
Damage: Young larvae chew on leaves and tassels; older larvae bore into stalks.
Prevention and controls: Remove old stalks and plant debris in fall or early spring before adults emerge; keep grass and weeds down; time planting to avoid insect growth cycle; hand-pick caterpillars.
Biological controls: Ladybugs; braconid wasps; tachinid flies; Bacillus thuringiensis.
Plant companions: Grow sunflowers as a trap crop.
Natural insecticides: Ryania; rotenone; sabadilla. Use with care, insecticides also kill beneficial insects.

Flea beetle

Scientific name: Order Coleoptera: Family Chrysomelidae
Description: Shiny black, brown, or bronze beetles with large hind legs to ⅛-inch long. Jump like fleas when disturbed.
Emergence time: Over-winter in the garden; emerge in spring.
Susceptible plants: Beans, beets, broccoli, Brussels sprouts, cabbage, cauliflower, chard, collards, corn, eggplants, kohlrabi, muskmelons, peppers, potatoes, radishes, spinach, tomatoes, turnips, watermelons.
Damage: Chews tiny holes in leaves; causes wilting and slows plant growth.
Prevention and controls: Cultivate often to disturb eggs; remove old plants and debris from the garden after harvest; plant susceptible plants near shade-giving crops, as beetles do not like shade; sprinkle wood ashes on plants; use garlic or hot pepper spray; cover with spun polyester blanket or other row covers; plant resistant varieties; time planting to avoid insect growth cycle.
Biological controls: Beneficial nematodes.
Natural insecticides: Diatomaceous earth; rotenone; pyrethrum; sabadilla; use with care, insecticides also kill beneficial insects.
Plant companions: Use bok choy, Chinese cabbage, and radishes as trap crops. Interplant crops with collards and tomatoes.
See Flea Beetle Organic Pest Control.

Harlequin bug

Scientific name: Murgantia histrionica
Description: Shiny black and red shield-shaped bug to ¼-inch long; large triangles on back.
Emergence time: Overwinter in debris; emerge in spring.
Susceptible plants: Brussels sprouts, cabbage, cauliflower, Chinese cabbage, collards, collards, kohlrabi, mustard, radish, and turnip.
Damage: Sucks sap from plants resulting in blotchy leaves, wilting, and death.
Prevention and controls: Handpick; remove weeds and debris from the garden; plant resistant varieties.
Biological controls: Sparrows and mockingbirds.
Natural insecticides: Liquid rotenone-pyrethrum, sabadilla; use with care, insecticides also kill beneficial insects.
Plant companions: Grow turnips and mustard greens as a trap crop.
See Harlequin Bug Organic Pest Control.

Hornworm, tomato hornworm

Scientific name: Manduca quinquemaculata
Description: Green caterpillar 3- to 5-inches long with white stripes; horn projects from the rear. The adult is a large, mottled gray or broth moth with orange spots on each side of the body.
Emergence time: Overwinters in soil; moths emerge in late spring to early summer.
Susceptible plants: Tomatoes, peppers, eggplant, potatoes, dill.
Damage: Chew holes in leaves and sometimes fruit.
Prevention and controls: Handpick; sprinkle dried hot peppers on the plant; diatomaceous earth around the base of plants; time planting to avoid insect growth cycle.
Biological controls: Bacillus thuringiensis, trichogramma wasps; braconid wasps.
Natural insecticides: Pyrethrum; rotenone; use with care, insecticides also kill beneficial insects.
Plant companions: Grow dill and four-o’clocks as a trap crop.
See Tomato Hornworm Organic Pest Control.

Imported cabbage worm

Scientific name: Artogeia rapae
Description: Adults are white butterflies; wings are white with black tips and 1 or 2 black spots on the forewing; wingspan of 1.5 inches. Larvae are velvety green caterpillars with a fine, light yellow stripe down the back.
Emergence time: Adult butterflies emerge in spring to lay eggs; three to five generations per year.
Susceptible plants: Cabbage family plants, cabbage, broccoli, cauliflower.
Damage: Chew holes in leaves; feed on undersides of leaves; produce pellets of dark green droppings; feed for 2-3 weeks, then pupate on the soil surface or in debris.
Prevention and controls: Handpick caterpillars and eggs; cover plants with floating row covers to prevent butterflies from laying eggs. Place yellow sticky trap among host plants.
Biological controls: Attract parasitic wasps, also yellowjacket wasps
Natural insecticides: Spray with Bacillus thuringiensis; spray with pyrethrins.
Plant companions: Cabbage family trap crops
See Imported Cabbage Worm Organic Pest Control.

Japanese beetle

Scientific name: Popillia japonica
Description: Adult metallic, blue-green beetle with bronze wing covers to ½-inch long. Grayish-brown grub with a brown head.
Emergence time: Adult beetles emerge in early summer after over-wintering underground.
Susceptible plants: Asparagus, beans, okra, peaches, raspberries, rhubarb, leaves of corn.
Damage: Grubs feed mostly on grassroots; adults feed on leaves and flowers of susceptible plants.
Prevention and controls: Handpick; remove all plant debris from the garden; grubs are discouraged by high soil pH; place commercial pheromone traps around the garden; time planting to avoid insect growth cycle.
Biological controls: Bacillus popilliae (milky spore) infects grubs, and requires wide application; beneficial nematodes.
Natural insecticides: Sabadilla, liquid rotenone, or pyrethrum controls adult beetles; use with care, insecticides also kill beneficial insects.
Plant companions: Larkspur foliage is toxic to beetles; geraniums repel beetles; smartweed repels insects. Grow light-colored geraniums and zinnias as trap crops.

Leafhopper

Scientific name: Order Homoptera: Family Cicadellidae
Description: Green, brown, or yellow bugs to ⅓-inch long with wedge-shaped wings; bugs move sideways.
Emergence time: Spring.
Susceptible plants: Potatoes, beans, carrots, celery, chard, eggplant, rhubarb, beets, lettuce, spinach, squash, and roses.
Damage: Suck juices from leaves and stems causing stunted, crinkled, mottled, curled leaves; some transmit viruses.
Prevention and controls. Insect prefers open areas so shelter susceptible plants; cover with spun polyester blanket or other row cover for about 4 weeks after plants sprout; plant resistant varieties.
Biological controls: Green lacewing, braconid wasps, Trichogramma wasps.
Natural insecticides: Diatomaceous earth; insecticidal soap; summer horticultural spray oil; liquid rotenone or pyrethrum; use with care, insecticides also kill beneficial insects.
Plant companions: Grow corn as a trap crop.
See Leafhopper Organic Pest Control.

Leaf miner

Scientific name: Order Diptera: Family Agromyzidae
Description: Tiny black flies about 1/10-inch long with yellow stripes. Larvae are pale green maggots.
Emergence time: Adults emerge in spring.
Susceptible plants: Beans, beets, cabbage, chard, lettuce, peppers, tomatoes.
Damage: Larvae tunnel inside leaves, stunting growth.
Prevention and controls: Destroy infected leaves; cultivate the garden to disturb the life cycle in fall; cover plants with spun polyester blanket or other row covers; time planting to avoid insect growth cycle.
Biological controls: Chickadees, finches, robins.
Natural insecticides: Light horticultural oil spray.
Plant companions: Grow radishes as a trap crop.
See Leaf Miner Organic Pest Control.

Mealybugs

Scientific name: Order Homoptera: Family Pseudococcidae
Description: Adult females have soft, oval, pinkish bodies covered with white powdery, or waxy fluff; about 1/10 inch long. Males are tiny, two-winged insects.
Emergence time: Several generations per year.
Susceptible plants: Potatoes, citrus, fruits, grapes, ornamentals.
Damage: Suck plant juices; feed on all parts of the plant. Attacked leaves wither and turn yellow; fruit may drop. Mealybugs excrete honeydew on leaves as they feed; excrement supports the growth of sooty mold.
Prevention and controls: Spray plant with stream of water or insecticidal soap; spray summer oil on plants that tolerate oil.
Biological controls: Native parasitic wasps.
Natural insecticides:
Plant companions:
See Mealybug Organic Pest Control.

Mexican bean beetle

Scientific name: Epilachna varivestis
Description: Round yellow- to copper-colored beetle with 16 black dots in three rows down the back, similar to a ladybug.
Emergence time: Adults emerge in spring.
Susceptible plants: Beans, squash.
Damage: Skeletonize leaves, plants dry out and die; also feed on bean pods and stems.
Prevention and controls: Destroy eggs; hand pick beetles; keep the garden free of plant debris to limit egg-laying habitat; time planting to avoid insect growth cycle: earlier plants are less susceptible; plant resistant varieties.
Biological controls: Ladybugs; Pediobius wasps kill larvae.
Natural insecticides: Liquid rotenone or pyrethrum; use with care, insecticides also kill beneficial insects. Rotenone dust; sabadilla; summer horticultural spray oil.
Plant companions: Plant nasturtiums, marigolds, savory, or garlic nearby. Grow lima beans as a trap crop.
See Mexican Bean Beetle Organic Pest Control.

Mites — see spider mites

Description:
Emergence time:
Susceptible plants:
Damage:
Prevention and controls:
Biological controls:
Natural insecticides:
Plant companions:

Nematodes

Scientific name: Phylum Nematoda
Description: Microscopic worms live in the soil and attack plant roots.
Emergence time:
Susceptible plants:
Damage: Roots become shriveled, with swellings called galls ranging in size from a pinhead to 1 inch in diameter. Galls cut off the flow of nutrients to the plant. Plants can become stunted and turn yellow; fruit can be undersized.
Prevention and controls: Grow plants resistant to nematode attack. Look for the letter “N” after the name of the vegetable variety, such as ‘Supersteak VFN’.
Biological controls:
Natural insecticides:
Plant companions: French marigolds repel nematodes.

Onion maggot

Scientific name: Delia antiqua
Description: Maggots are brown, legless, hump-backed, and hairy to ⅓-inch long.
Emergence time: Adult flies emerge in late spring to lay eggs at the base of plants.
Susceptible plants: Onion, radishes.
Damage: Tunnel into the lower stem of onion near bulb, damaging neck.
Prevention and controls: Remove and destroy infested plants; avoid planting crops too closely or full crops in one place. Use wood ashes and diatomaceous earth as a barrier.
Biological controls: Beneficial nematodes, predatory flies, spiders, ichneumonid wasps.
Natural insecticides: None.
Plant companions: Intercrop with plants that are not susceptible to onion maggot.

Root maggots

Scientific name: Several species exist; including cabbage maggot, carrot maggot, and onion maggot.
Description: Fly larvae resemble common house fly maggots. White, peg-shaped, 1/4 inch long
Emergence time: Fly lays eggs at the plant base; maggots crawl into the soil where they feed on the roots.
Susceptible plants: Cabbage, carrot, onion
Damage: Roots eaten, leaves wilt, and the plant is stunted.
Prevention and controls: Dust with wood ashes, rotenone, pyrethrum, and diatomaceous earth; garlic spray; cover the soil with black plastic mulch and plant through the plastic to prevent adult flies from laying eggs.
Biological controls:
Natural insecticides:
Plant companions:

Slug and snails

Scientific name: Class Mollusca
Description: Mollusk; brown, gray, white, purple, or yellow snails without shells to 2 inches long.
Emergence time: Early spring; prefer cool temperatures.
Susceptible plants: Almost all vegetables.
Damage: Eat large, ragged holes in leaves, stems, and fruit.
Prevention and controls: Handpick and destroy; sprinkle slugs with salt; place protective borders of sand, lime, or ashes around plants; mulch with wood shavings or oak leaves; trap with saucers of stale beer set out at soil level; place boards or newspapers as traps; border with copper bands; protect plants in plastic tunnels.
Biological controls: Garden birds, woodpeckers, robins; snakes, toads, turtles; black rove beetles, centipedes, ground beetles, and soldier beetles eat slugs and slug eggs.
Natural insecticides: Diatomaceous earth.
Plant companions: Low-growing shade plants will shelter slugs; handpick from beneath the shelter.
See Slug and Snail Organic Pest Control.

Spider mite

Scientific name: Order Acarina: Family Tetranychidae
Description: Tiny spider-like arachnids: red, black, or brown.
Emergence time: Hot, dry weather; many generations in a year.
Susceptible plants: All vegetables and fruit crops.
Damage: Suck plant juices causing stippled leaves that are yellow, dry, and drop.
Prevention and controls: Spray cold water or solution of water, wheat flour, buttermilk on leaves; soapy water sprays; light horticultural oil sprays.
Biological controls: Ladybugs; lacewings, predatory mites.
Natural insecticides: Liquid rotenone or pyrethrum; use with care, insecticides also kill beneficial insects; insecticidal soap; horticultural oil spray.
Plant companions: None.
See Spider Mite Organic Pest Control.

Squash bug, stink bug

Scientific name: Anasa tristis
Description: Flat-backed, shield-shaped black or brownish bug to 5/8-inch long with a triangle on its back.
Emergence time: Adults emerge when squash vines begin to grow.
Susceptible plants: Vine crops: cucumbers, muskmelons, pumpkins, squash, watermelons.
Damage: Sucks plant juices and injects toxins resulting in wilt and death.
Prevention and controls: Handpick; keep the garden free of debris and hiding places; use trellis to raise off of ground away from bugs; dust with wood ashes and lime; cover with spun polyester blanket or other row covers; plant resistant varieties; time planting to avoid insect growth cycle.
Biological controls: Tachinid flies
Natural insecticides: Sabadilla; rotenone dust; liquid rotenone or pyrethrum; use with care, insecticides also kill beneficial insects.
Plant companions: Plant trap crops: marigolds, radishes, tansy, or nasturtiums nearby.
See Squash Bug Organic Pest Control.

Squash vine borer

Scientific name: Melittia cucurbitae
Description: Fat, white caterpillar with a brown head. The adult is a moth with red, black, and copper rings 1½-inch long.
Emergence time: Late spring.
Susceptible plants: Vine crops: cucumbers, muskmelons, pumpkins, squash, watermelon.
Damage: Bores into stems stems and the plant wilts.
Prevention and controls: Wrap strips of nylon stocking around stems to keep adults from laying eggs; mound soil up to blossoms and keep covered; cover with spun polyester blanket or other row covers; plant resistant varieties; time planting to avoid insect growth cycle.
Biological controls: Trichogramma wasps.
Natural insecticides: Rotenone; sabadilla; use with care, insecticides also kill beneficial insects. Also diatomaceous earth.
Plant companions: Plant early summer squash around late winter varieties as a trap crop. Destroy infested early summer squash and replant for a late crop.
Se Squash Vine Borer Organic Pest Control.

striped cucumber beetle illustration — Striped cucumber beetle, illustration

Spotted and striped cucumber beetle

Scientific name: Diabrotica undecimpunctata howardi (spotted cucumber beetle); Acalymma vittatum (striped cucumber beetle)
Description: Yellow beetle with black head and three wide black stripes or spots on the wing covers; beetle to ¼-inch long. Larvae: slender, white grubs.
Emergence time: Adults emerge in late spring.
Susceptible plants: Cucumbers and other vine plants; beans, corn, peas, and flowers of many plants. Damage. Larvae feed on roots and stems; adults feed on leaves and shots; can transmit wilt and mosaic virus.
Prevention and controls: Handpick; mulch around plants; cover plants with spun polyester blanket or other row covers; plant resistant varieties; dust with wood ashes or rock phosphate; grow plants on trellises; time planting to avoid insect growth cycle.
Biological controls: Braconid wasps, tachinid flies, beneficial nematodes.
Natural insecticides: Liquid rotenone or pyrethrum; sabadilla; use with care, insecticides also kill beneficial insects.
Plant companions: Interplant with catnip, tansy, or radishes.
See Cucumber Beetle Organic Pest Control.

Tarnished plant bug

Scientific name: Lygus lineolaris
Description: Oval, brown, and mottled yellow and black bug to ¼-inch long; very mobile.
Emergence time: Spring.
Susceptible plants: Beans, celery, chard, lettuce, strawberries, peaches, and pears.
Damage: Suck juices from stems, buds, and fruits leaving black spots and pitting; injects a toxin that deforms flowers, blackens terminal shoots, dwarfs, and pits fruit; can carry fireblight.
Prevention and controls: Keep the garden free of plant debris; white sticky traps.
Biological controls: None.
Natural insecticides: Sabadilla dust; liquid rotenone or pyrethrum; use with care, insecticides also kill beneficial insects.
Plant companions: None.
See Tarnished Plant Bug Organic Pest Control.

Thrips

Scientific name: Order Thysanoptera: Family Thjripidae
Description: Very tiny to minute insects, yellow, brown, or black with narrow, fringed wings; leave dark fecal pellets behind.
Emergence time: Five to 15 generations per year; slow reproduction in winter.
Susceptible plants: Onions, beans, cucumbers, corn, melons, squash, tomatoes, and many flowers.
Damage: Scrape plant tissue, scar leaves, stems, and fruits; transmit viruses.
Prevention and controls: Keep the garden free of weeds and debris; place aluminum foil mulch around plants; diatomaceous earth; soapy water sprays; yellow sticky traps.
Biological controls: Green lacewings, ladybugs, predatory mites.
Natural insecticides: Liquid rotenone or pyrethrum; insecticidal soap; use with care, insecticides also kill beneficial insects; tobacco and sulfur dust.
Plant companions: None.

Tomato fruitworm / corn earworm

Scientific name: Helicoverpa zea
Description: Spiny caterpillar, white, green, or red to 1½ inches long. The adult is a brown moth.
Emergence time: Late spring.
Susceptible plants: Tomatoes
Damage: Feed buds and leaves and later bore into fruit.
Prevention and controls: Hand pick from. Remove debris from the garden in the fall and cultivate thoroughly.
Biological controls: Trichogramma wasps, Bacillus thuringiensis, beneficial nematodes.
Natural insecticides: Spray young plants with horticultural oil mixed with Bacillus thuringiensis every 2 weeks. Rotenone; use with care, insecticides also kill beneficial insects.
Plant companions: Plant smartweed as a trap crop.
See Corn Earworm-Tomato Fruitworm Organic Pest Control.

Weevils

Scientific name: Order Coleoptera: Family Curculionidae
Description: Many types of small beetles; usually brown or black and tear-shaped with hard-shelled bodies and long snots. Larvae are small whitish grubs.
Emergence time: Overwinter in soil; adults emerge in late spring.
Susceptible plants: Most vegetables, also apples, blueberries, cherries, peaches, pears, plums, raspberries, and strawberries.
Damage: Puncture holes in leaves stems, and fruits, sometimes defoliating plants. Larvae eat roots, fruit, and stems.
Prevention and controls: Hill up soil around stems of sweet potato vines; rotate crops; remove plant debris; time planting to avoid insect growth cycle.
Biological controls: Beneficial nematodes, spiders.
Natural insecticides: Diatomaceous earth. Pyrethrum, rotenone: use with care, insecticides also kill beneficial insects.
Plant companions: None.
See Weevil Organic Pest Control.

Whitefly

Scientific name: Order Homoptera: Family Aleyrodidae
Description: Adults are white about 1/12 inch long; with wings covered with powdery white scales. Nymphs are translucent legless scales. Feed and lay eggs on the undersides of leaves; fly up in a cloud when disturbed.
Emergence time: Eggs over-winter hatch in early spring; many generations throughout the growing season.
Susceptible plants: Cucumbers, melons, squash, tomatoes, citrus, and many weeds.
Damage: Sucks sap from leaves causing foliage to curl, pucker, and yellow; loss of plant vigor; some transmits diseases such as mosaic; excrement supports black, sooty mold; attracts ants.
Prevention and controls: Spray away with strong water; or soapy water spray; as a lure, use yellow sticky traps near the tops of plants; insecticidal soap; neem oil; cover plant with Spun polyester blanket or other row covers.
Biological controls: Ladybugs; parasitic wasps.
Natural insecticides: Insecticidal soap; nicotine. Pyrethrum; sabadilla; use with care, insecticides also kill beneficial insects. Light horticultural oil spray.
Plant companions: Plant aster and parsley family plants also alyssum or clover to attract whitefly-eating beneficial insects. Onions and garlic may repel whiteflies. Trap crops: eggplant and squash.
See Whitefly Organic Pest Control.

Wireworm

Scientific name: Limonius spp.
Description: Larvae of click beetles: ⅓- to 1½-inches long; dark brown to yellowish jointed, cylindrical, hard-shelled, legless worm often confused with a millipede.
Emergence time. Beetles lay eggs in the soil in spring; worms emerge and take 2 to 6 years to reach adulthood.
Damage: Chews roots, seeds, and tubers; plants wilt and die.
Susceptible plants: Potatoes, beets, beans, lettuce, carrots, cabbage, corn, onions, muskmelons, and turnips.
Prevention and controls: Cultivate to expose worms and discourage egg laying; plant green manure crops such as clover. Potato trap: bury halved potatoes cut side down in the soil to trap worms then discard potatoes after two days.
Biological controls: Beneficial nematodes.
Natural insecticides: Tobacco dust or tobacco tea.
Plant companions: Alfalfa and clover crops repel wireworms.

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