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Working the Bugs Out
Aphids and harmful pests
Photo: Dwight Kuhn
Snails and harmful pests
Photo: Dwight Kuhn
June beetle larvae and harmful insects
Photo: Dwight Kuhn
spider mites and harmful insects
Photo: Ronn West
Gypsy moth laying eggs and harmful insects
Photo: Dwight Kuhn
two Japanese beetles on a leaf
Photo: Dwight Kuhn
Grasshopper
Photo: Dwight Kuhn
forcefully spraying plants to control pests
Photo: Walter Chandoha
Seedling with collar to control pests
Photo: Ron West
Wasp egg card for pest control
Photo: Ron West
nematode sponge for pest control
Photo: Ken Miller
Ladybug eating harmful insects
Photo: Dwight Kuhn
Adult parasitic wasp cocoons attached to a hornworm
Photo [COPYRIGHT] Dwight Kuhn
Adult parasitic wasp and aphid mummy
Photo [COPYRIGHT] Dwight Kuhn
Adult green lacewings
Photo [COPYRIGHT] Dwight Kuhn

Aphids
Description: Small, soft-bodied sucking insects; green, pink, yellow, red, brown or black
Where: They congregate at succulent stem tips and underside of tender leaves. Found throughout North America
Damage: Curled leaves, yellow foliage, sticky honeydew, transmission of plant diseases
Controls: Forceful water spray, insecticidal soap, horticultural oil, ladybugs, lacewings, neem

Slugs/Snails
Description: Soft-bodied, legless soil dwellers with shells (snails) or without shells (slugs)
Where: Found in moist, shady areas throughout North America. Hostas and fruits are favorite plants
Damage: Chew holes in leaves; leave slime trails
Controls: Use drip irrigation to keep garden drier. Also try Sluggo and Escar-go baits, copper barriers around individual plants, diatomaceous earth, saucers of beer and trap boards. Toads, snakes, ducks and geese feed on slugs

Lawn Grubs
Description: May/June beetle adult is reddish brown to black with hard shell; Southern masked chafer adult is light brown; Northern masked chafer adult is chestnut brown. Larvae of all are 1-inch long, white, C-shaped grubs
Where: May/June beetle found throughout North America. Southern masked chafer in Midwest and Southeast. Northern masked chafer in Northeast. Larvae live in soil under turfgrass
Damage: Adults of May/June beetle chew foliage of oak, willow, apple, poplar and birch trees. Most damage from larvae comes from their chewing on grass roots; turf turns brown from lack of roots in summer
Controls: Predatory nematodes (Steinernema and Heterorhabditis, Grub Guard, Grub-Away) mixed with water and applied to soil

Spider Mites
Description: Reddish-brown or pale, tiny, eight-legged. Often produce webbing more visible than the mites themselves
Where: In dry areas throughout North America. Common in warm locations; most often on leaf underside. Roses, beans and marigolds are favorites
Damage: Suck plant juices from leaves. Create silvery stippling on leaf; leaves yellow and brown; webbing
Controls: Forceful water spray, insecticidal soap, horticultural oil, lacewings, ladybugs, predatory mites (Galandromus, Phytoseiulus), neem, sulfur dust.

Gypsy Moth
Description: Adult female is a creamy white moth; male brownish moth. Larvae are black hairy caterpillars with five pairs of blue spots and six pairs of red spots on back. Egg masses are buff-colored
Where: Throughout Northeastern U.S.; isolated elsewhere. Egg cases are laid everywhere. Larvae feed on the foliage of shade trees
Damage: They defoliate trees by chewing leaves; oaks are a favorite
Controls: Handpick and destroy egg masses; spray B.t. when larvae are young

Japanese Beetle
Description: Adults are metallic green with coppery wing covers; larvae are grayish-white grub
Where: Concentrated in eastern third of U.S.; less common elsewhere. Adults feed on foliage of more than 300 species of trees, shrubs and flowers; larvae in soil
Damage: Adults chew leaves and flowers of plants; larvae feed on roots
Controls: For larvae: Milky Spore or nematodes (Grub Guard, Grub-Away). For adults: neem or rotenone; place Japanese beetle pheromone traps outside garden, not near plants attractive to the beetle

Grasshoppers
Description: Green, brown or reddish yellow with enlarged hind legs for jumping
Where: Throughout North America; most common in dry areas. They prefer vegetables and flowers, though they might eat most any plant
Damage: All stages chew leaves and stems of many kinds of plants. They feed during the day
Controls: Keep garden watered well. Hot Pepper Wax discourages feeding; Nolo Bait, a protozoan that kills only grasshoppers, is effective if applied over at least several acres early in they year. Guinea hens and turkeys eat grasshoppers

A forceful spray of water knocks pest like aphiuds and spider mites off plants, and they won't find their way back. Spray plants routinely.

Place a stiff paper collar around young seedlings to prevent cutworms from chewing through the stem, which kills the plant.

Thousands of eggs of the trichogramma wasp are attached to this card, which is placed in the garden. Hatched wasps destroy the eggs of plant-eating caterpillars.

Millions of microscopic beneficial nematodes are attached to this blue sponge. Swishing the sponge in water releases the live nematodes, which are then sprayed on the lawn to seek out and kill grubs.

If you think the only good bug is a dead bug, think again. Many of the insects in our midst are beneficial—the natural enemies of insects that feed on plants.

Ladybugs are beneficial both as winged adults and soft-bodied larvae, feeding primarily on aphids, as shown below. They also feed on mites, scales, and mealybugs.

Beneficial bug:

White cocoons of a parasitic wasp stick to the back of a tomato hornworm. Each cocoon produces a wasp that will seek out another hornworm to attach to.


Beneficial bug:

An adult parasitic wasp emerges from an "aphid mummy" (below) after developing from an egg laid inside the living aphid.

Beneficial bug:

Adult green lacewings eat only nectar, pollen, and aphid honeydew, but the alligator-shaped larvae are extremely voracious predators that suck the body fluids from prey. Below, an impaled aphid is the victim.

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Biological Controls

Researchers have figured out ingenious ways to manipulate natural controls to reduce pests. Some traps use pheromones, the natural perfume that pests use to find each other and mate. Codling moths and peach tree borers can be controlled with pheromone traps. But be cautious about using Japanese beetle pheromone traps. They draw the beetles to the general area but not necessarily into the trap. The result is an increase in Japanese beetles rather than control. The traps can be useful, however, in large yards when they are placed far away from prized plants.

Numerous beneficial insects are available commercially at nurseries, by mail and on the Web. But you'll need to persuade these insects to stay in your garden so they don't all fly away shortly after release. Ladybugs, for example, are more apt to stay when you release them in the evening, dispense only a couple per square yard and spray plants with a sugar-water solution to mimic the honeydew secreted by aphids, their favorite taste treat.

Another example of beneficial insects are parasites that kill pests by laying eggs inside the pests' body. After the eggs hatch, the larvae eat the pests from the inside out. Not a pretty picture, but it works in the garden.

Millions of parasites occur naturally, and you'll find a few available commercially. Most common are tiny wasps called trichogramma. They lay their eggs in moth and butterfly eggs that become plant-chewing caterpillars. These wasps are perfectly harmless to people and animals.

Also available commercially are parasitic nematodes that target insects which spend part of their life below ground. Lawn grubs, Japanese beetle larvae and weevil larvae are examples of pests nematodes control. Nematodes work best in loamy soil in mild climates. They are least effective in extremely sandy or clay soils, in dry areas and at extreme temperatures. You'll find them sold in either in a paste form or on a sponge, under such names as Grub-Away and Grub Guard. Mix with water and spray on moistened soil or lawn.

Insects, like humans and other animals, get diseases. Some disease-causing organisms are sold to gardeners to target specific pests. Bacillus thuringiensis (B.t., Dipel, MVP), a bacterium that paralyzes the gut only of plant-chewing caterpillars, is one of the most widely available. Another is milky spore, which attacks Japanese beetle larvae but not the adults.

Photo Gallery: Meet the Good Bugs
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