Nothing is quite as depressing to a gardener than walking out in the morning to see that your flowers or vegetables have been chewed by insects. This chapter will discuss when to take action, and how to use beneficial insects to fight the insect pests in your garden. If a more direct approach is needed, instructions on how to make traps and control sprays are included to help you win the war over the pests.
The following is an alphabetical list of common plants and the pests that love them. If known, the most common pest is italicized.
ASTERS – Aphids, blister beetles, cucumber beetles, European corn borers, leafhoppers, slugs, snails, tarnished plant bugs, thrips, and whiteflies
BEGONIAS – Aphids, mealybugs, nematodes, slugs, snails, spider mites, thrips, and whiteflies
CALENDULAS – Aphids, cabbage loopers, corn earworms, cutworms, leafhoppers, and spider mites
CARNATIONS – Aphids, cabbage loopers, cutworms, mealybugs, slugs, snails, spider mites, spittlebugs, and thrips
CHRYSANTHEMUMS – Aphids, cabbage loopers, corn earworms, cucumber beetles, cutworms, European corn borers, lacebugs, leaf miners, nematodes, slugs, snails, spider mites, tarnished plant bugs, thrips, and whiteflies
COSMOS – Aphids, beetles, borers, leafhoppers, spider mites, and thrips
DAHLIAS – Aphids, cucumber beetles, European corn borers, leafhoppers, leaf miners, nematodes, slugs, snails, and tarnished plant bugs
DELPHINIUMS – Aphids, cutworms, leafhoppers, slugs, snails, spider mites, and thrips
GERANIUMS – Aphids, geranium budworms, mealybugs, slugs, snails, spider mites, and whiteflies
GLADIOLUS – Aphids, cutworms, European corn borers, spider mites, tarnished plant bugs, and thrips
HOLLYHOCKS – Aphids, European corn borers, leafhoppers, mealybugs, nematodes, slugs, snails, spider mites, thrips, and whiteflies
IMPATIENS – Aphids, cucumber beetles, mealybugs, nematodes, scale insects, slugs, snails, spider mites, and tarnished plant bugs
IRIS – Aphids, borers, nematodes, slugs, snails, spider mites, thrips, weevils, whiteflies, and wireworms
LILIES – Aphids, mealybugs, nematodes, root maggots, scale insects, slugs, snails, spider mites, and thrips
MARIGOLDS – Cabbage loopers, cutworms, leaf miners, slugs, snails, spider mites, and tarnished plant bugs
NARCISSUS – Aphids, mealybugs, mites, narcissus bulb flies, nematodes, slugs, snails, and thrips
PANSIES – Aphids, cutworms, flea beetles, mealybugs, nematodes, slugs, snails, spider mites, and wireworms
PEONIES – Rose chafers and thrips
PETUNIAS – Armyworms, blister beetles, cabbage loopers, Colorado potato beetles, flea beetles, geranium budworms, hornworms, slugs, and snails
PHLOX – Aphids, leafhoppers, spider mites, and wireworms
POPPIES – Aphids, corn earworms, leafhoppers, mealybugs, rose chafers, slugs, snails, and tarnished plant bugs
PRIMROSES – Leaf miners, slugs, snails, spider mites, and whiteflies
SNAPDRAGONS – Aphids, cabbage loopers, corn earworms, nematodes, slugs, snails, and spider mites
SWEET PEAS – Aphids, slugs, and snails
TULIPS – Aphids, spider mites, and wireworms
ZINNIAS – Aphids, blister beetles, cucumber beetles, European corn borers, flea beetles, Japanese beetles, mealybugs, and tarnished plant bugs
APPLES – Aphids, borers, cankerworms, cicadas, codling moths, cucumber beetles, fall webworms, fruit flies, green fig beetles, gypsy moths, Japanese beetles, leafhoppers, leaf miners, leaf rollers, mealybugs, psyllids, sawflies, scale insects, spider mites, tarnished plant bugs, tent caterpillars, thrips, tussock moths, and weevils
APRICOTS – Aphids, borers, codling moths, green fig beetles, plum curculios, scale insects, spider mites, and whiteflies
BLACKBERRIES AND RASPBERRIES – Aphids, borers, cutworms, fruit flies, Japanese beetles, leafhoppers, leaf rollers, psyllids, red-berry mites, root weevils, sawflies, scale insects, thrips, and whiteflies
BLUEBERRIES – Fruit flies, Japanese beetles, nematodes, scale insects, and weevils
CHERRIES – Aphids, borers, cankerworms, fall webworms, fruit flies, gypsy moths, Japanese beetles, leaf rollers, nematodes, plum curculios, sawflies, scale insects, spider mites, tent caterpillars, and tussock moths
CITRUS – Ants, aphids, leaf rollers, mealybugs, mites, scale insects, and whiteflies
CURRANTS – Aphids, borers, and fruit flies
FIGS – Ants and green fig beetles
GRAPES – Aphids, armyworms, borers, grape leaf skeletonizers, Japanese beetles, leafhoppers, leaf rollers, mealybugs, nematodes, rose chafers, scale insects, spider mites, thrips, and whiteflies
PEACHES AND NECTARINES – Aphids, borers, cankerworms, cicadas, curculios, fall webworms, fruit flies, green fig beetles, Japanese beetles, leaf rollers, mealybugs, nematodes, scale insects, spider mites, tarnished plant bugs, tent caterpillars, thrips, and tussock moths
PEARS – Aphids, borers, cankerworms, codling moths, curculios, flea beetles, fruit flies, leaf miners, leaf rollers, mealybugs, psyllids, sawflies, scale insects, spider mites, tarnished plant bugs, tent caterpillars, thrips, and tussock moths
PLUMS AND PRUNES – Aphids, borers, cankerworms, curculios, fruit flies, Japanese beetles, leaf rollers, mealybugs, sawflies, scale insects, spider mites, tent caterpillars, and tussock moths
QUINCES – Aphids, borers, codling moths, fall webworms, scale insects, and tent caterpillars
STRAWBERRIES – Aphids, cutworms, flea beetles, leaf rollers, mealybugs, nematodes, root weevils, scale insect, slugs, snails, spider mites, sowbugs, tarnished plant bugs, thrips, and wireworms
WALNUTS – Aphids, caterpillars, codling moths, leaf rollers, scales, spider mites, and walnut husk flies
ASHES – Aphids, borers, lacebugs, scale insects, tent caterpillars, and whiteflies
AZALEAS AND RHODODENDRONS – Aphids, borers, lacebugs, leafminers, root weevils, scale insects, spider mites, thrips, and whiteflies
CAMELLIAS – Aphids, leaf galls, and scale insects
CLEMATIS – Earwigs, slugs, and snails
CRAPE MYRTLES – Aphids and scale insects
DOGWOODS – Borers, cicadas, leafhoppers, and scale insects
ELMS – Aphids, bark beetles, borers, cankerworms, elm leaf beetles, leafhoppers, leaf rollers, and scale insects
FUCHSIAS – Aphids, fuchsia mites, mealybugs, and whiteflies
HIBISCUS – Aphids, beetles, mealybugs, scale insects, and whiteflies
HOLLIES – Beetles, moths, leaf miners, nematodes, scale insects, spider mites, and whiteflies
HONEYSUCKLES – Aphids, flea beetles, mealybugs, mites, scale insects, and whiteflies
HYDRANGEAS – Aphids, scale insects, slugs, and snails
IVIES – Aphids, scale insects, slugs, and snails
JUNIPERS – Aphids, bagworms, borers, leaf miners, scale insects, and spider mites
LILACS – Aphids, borers, cucumber beetles, leaf miners, mealybugs, scale insects, spider mites, and whiteflies
MAGNOLIAS – Loopers, mealybugs, scale insects, and thrips
MAPLES – Aphids, bagworms, borers, cankerworms, gypsy moths, leafhoppers, mealybugs, nematodes, scale insects, spider mites, thrips, and whiteflies
MULBERRIES – Fall webworms, mites, nematodes, scale insects, and whiteflies
OAKS – Aphids, bark beetles, borers, cankerworms, cicadas, gall wasps, gypsy moths, Japanese beetles, lacebugs, leaf miners, leaf rollers, scale insects, spider mites, tent caterpillars, tussock moths, and whiteflies
PALMS – Borers, leaf skeletonizers, mealybugs, nematodes, scale insects, spider mites, and thrips
PINES – Aphids, bark beetles, borers, nematodes, sawflies, scale insects, and spider mites
ROSES – Aphids, borers, corn earworms, cucumber beetles, curculios, fall webworms, harlequin bugs, Japanese beetles, leafhoppers, leaf rollers, nematodes, rose chafers, sawflies, scale insects, slugs, snails, spider mites, thrips, and whiteflies
SPRUCES – Aphids, borers, budworms, needle miners, sawflies, scale insects, spider mites, and weevils
SYCAMORES – Aphids, borers, lacebugs, psyllids, and scale insects
WILLOWS – Aphids, borers, fall webworms, sawflies, scale insects, and tussock moths
ASPARAGUS – Aphids, asparagus beetles, harlequin bugs, Japanese beetles, slugs, snails, spider mites, and tarnished plant bugs
BASIL – Cutworms
BEANS – Aphids, armyworms, blister beetles, corn earworms, cucumber beetles, cutworms, European corn borers, flea beetles, harlequin bugs, Japanese beetles, leafhoppers, leaf miners, mealybugs, Mexican bean beetles, nematodes, slugs, snails, spider mites, tarnished plant bugs, thrips, weevils, whiteflies, and wireworms
BEETS – Aphids, armyworms, blister beetles, flea beetles, leafhoppers, leaf miners, nematodes, webworms, and wireworms
BROCCOLI – Aphids, cabbageworms, cabbage loopers, cabbage root maggots, cutworms, and flea beetles
CABBAGES AND OTHER CABBAGE-FAMILY CROPS, SUCH AS KOHLRABI, BRUSSELS SPROUTS, AND CAULIFLOWER – Aphids, armyworms, blister beetles, cabbage loopers, cutworms, earwigs, flea beetles, harlequin bugs, imported cabbageworms, leaf miners, nematodes, root maggots, root weevils, slugs, snails, symphylans, tarnished plant bugs, and thrips
CANTALOUPES – See Cucumbers
CARROTS – Aphids, blister beetles, carrot rust flies, flea beetles, leafhoppers, parsley worms, root-knot nematodes, root weevils, thrips, and wireworms
CELERY – Aphids, cabbage loopers, flea beetles, leafhoppers, mites, nematodes, parsleyworms, root weevils, slugs, tarnished plant bugs, and thrips
CHIVES – See Onions
CORN – Aphids, armyworms, blister beetles, chinch bugs, corn earworms, cucumber beetle larvae, cutworms, earwigs, European corn borers, flea beetles, harlequin bugs, Japanese beetles, June beetles, nematodes, and wireworms
CUCUMBERS AND OTHER MEMBERS OF THE CUCURBITS FAMILY, SUCH AS MELON, PUMPKIN, AND SQUASH – Aphids, blister beetles, cucumber beetles, flea beetles, harlequin bugs, leafhoppers, nematodes, spider mites, squash bugs, squash vine borers, tarnished plant bugs, thrips, and whiteflies
DILL – Aphids and parsleyworms
EGGPLANTS – Aphids, blister beetles, Colorado potato beetles, cutworms, flea beetles, harlequin bugs, hornworms, leafhoppers, nematodes, potato tuberworms, spider mites, and whiteflies
FENNEL – Parsleyworms and slugs
GARLIC – Aphids, nematodes, onion maggots, root maggots, and thrips
LETTUCE – Aphids, armyworms, cabbage loopers, corn earworms, flea beetles, harlequin bugs, leafhoppers, leaf miners, slugs, snails, tarnished plant bugs, and whiteflies
MELONS – See Cucumbers
MINT – Aphids, borers, cutworms, flea beetles, loopers, nematodes, spider mites, and weevils
OKRA – Fire ants, green fig beetles, Japanese beetles, and nematodes
ONIONS AND OTHER ONION FAMILY CROPS, SUCH AS LEEKS AND CHIVES – Blister beetles, cutworms, green fig beetles, nematodes, onion maggots, thrips, and wireworms
OREGANO – Aphids, leaf miners, and spider mites
PARSLEY – Parsleyworms
PEAS – Aphids, armyworms, blister beetles, cabbage loopers, corn earworms, cucumber beetles, flea beetles, leafhoppers, nematodes, spider mites, thrips, and weevils
PEPPERS – Aphids, blister beetles, Colorado potato beetles, corn earworms, European corn borers, flea beetles, hornworms, leafhoppers, leaf miners, leaf rollers, nematodes, potato tuberworms, spider mites, and whiteflies
POTATOES – Aphids, blister beetles, cabbage loopers, Colorado potato beetles, cucumber beetles, European corn borers, flea beetles, harlequin bugs, hornworms, June beetles, leafhoppers, leaf miners, nematodes, potato tuberworms, psyllids, root maggots, root weevils, tarnished plant bugs, and wireworms
RADISHES – Cabbage root maggots, flea beetles, and harlequin bugs
RHUBARB – Caterpillars, Japanese beetles, leafhoppers, and slugs
SPINACH – Aphids, blister beetles, cabbage loopers, flea beetles, imported cabbageworms, leafhoppers, leaf miners, and root weevils
SQUASH – Aphids, cucumber beetles, leafhoppers, nematodes, squash vine borers, and spider mites
SWEET POTATOES – Aphids, flea beetles, nematodes, sweet potato weevils, and wireworms
SWISS CHARD – Aphids, armyworms, blister beetles, flea beetles, grasshoppers, leafhoppers, and leaf miners
TOMATOES – Aphids, armyworms, blister beetles, cabbage loopers, Colorado potato beetles, corn earworms, cucumber beetles, cutworms, European corn borers, flea beetles, hornworms, leafhoppers, nematodes, potato tuberworms, psyllids, slugs, snails, spider mites, thrips, and whiteflies
TURNIPS – Aphids, cabbage root maggots, flea beetles, and wireworms
BENT GRASS – Chinch bugs, cutworms, grubs, mole crickets, and sod webworms
BERMUDA GRASS – Armyworms, sowbugs, cutworms, grubs, mealybugs, mites, nematodes, and sod webworms
BUFFALO GRASS – Chinch bugs, mealybugs, mites, and webworms
DICHONDRA – Cutworms, flea beetles, nematodes, slugs, snails, and spider mites
FESCUE – Chinch bugs, cutworms, grubs, leafhoppers, and sod webworms
KENTUCKY BLUEGRASS – Chinch bugs, cutworms, grubs, leafhoppers, and sod webworms
RYEGRASS (ANNUAL) – Cutworms, grubs, and leafhoppers
RYEGRASS (PERENNIAL) – Cutworms, grubs, leafhoppers, and sod webworms
ST. AUGUSTINE GRASS – Armyworms, chinch bugs, cutworms, grubs, mole crickets, and sod webworms
ZOYSIA – Armyworms, billbugs, chinch bugs, grubs, and sod webworms
For many gardeners, a good offense is better than a good defense. As soon as the first seed is planted, the pest control measures start. This plan can work well, but many times it involves using lots of chemicals to be effective. The question is, when is it necessary to step in with pest control measures? Take this short quiz to determine if you’re overprotecting your garden.
— Do you start spraying before you see any bugs?
— When you see a bug, do you start every pest control measure you know and treat your whole garden?
— When you find a bug, do you stop everything and check every plant in your garden?
— Do you believe that most bugs in your garden are “bad guys”?
If you think that answering yes to most of these questions is pretty extreme, then you probably aren’t overprotecting your garden. However, if you found yourself answering most of these questions in the affirmative, then you may need to pull back a little bit. Here are a few facts that may help you do that:
— Over 95 percent of bugs found in your garden are either beneficial or do no harm at all.
— Spot-treating plants that have pests is better than treating your whole garden.
— Water is one of the most effective weapons against pests.
— Over time, beneficial insects are likely to do just as good a job of controlling pest insects as spraying chemicals.
— Ensuring that your plants are healthy and vigorous is the best preventative measure you can take for your garden.
Okay, you understand all of this. What should you do now?
— Keep a garden log. Write down when and where you planted everything. List the dates when you saw bugs and on which plant. Next year, try planting later or earlier when the bugs aren’t a problem. (It is good to keep a log for plant diseases too; in this case, write down when you first noted a plant disease starting.)
— Know your enemy. If you have bugs in your garden, find out what they are. The same is true when it comes to plant diseases. Many books, such as field guides and gardening books, offer extensive insect identifications. There is usually someone on the staff at your local nursery who will know the local pests. The nearby university, natural history museum, or county extension office will also be able to help you identify insects. You may find that the bugs in your garden aren’t doing anything harmful at all!
— Use specific pest-control strategies in your garden. If you have aphids, don’t treat your garden with Bacillus thuringiensi (Bt) for caterpillars, just in case. Bt is a bacterium used as an insecticide. There are more than thirty-five varieties, several of which are available to home gardeners. Bt (kurstaki) affects common pest caterpillars in the butterfly and moth family. It can also hurt beneficial caterpillars, so be careful when using it. Bt (israelensi) affects the larvae of blackflies, fungus gnats, and mosquitoes. Bt (san diego) affects certain leaf-feeding insects, such as black vine weevils, boll weevils, Colorado potato beetles, and elm leaf beetles. As with all pesticides, even those that are considered nontoxic to people, read the label carefully before using.
— If you decide to bring in beneficial insects, make sure they are effective in your area.
— Plan ahead when planting. Make sure the soil is in top condition before planting to ensure healthy plants.
— Plant only plants that grow well in your area or are resistant to diseases found in your area.
— Finally, decide how much damage you are willing to accept. Having an organic garden means finding a balance between the good bugs and the bad bugs. You must expect some insect damage. How much is too much for you?
You’ve done all this, yet find you still have too many holes in your lettuce leaves or aphids on your cabbages. Then it is time to start taking pest control measures.
— First, identify the pest insect. Use sticky traps or collect the pest from the plant. Use field guides or take the insect to a nursery, university, or agricultural extension office for identification.
— Select the pest control measure that will have the least effect on beneficial insects and the environment, such as using a trap that lures the pest away from your plants, or hand-picking. Hand-picking is a great solution for hornworm caterpillars, for example.
— Spray only the affected plant. Soap spray is one example of a good control measure, but only spray where necessary.
— Select a pest control measure that targets the pest. Use the insect’s own biology against it. An insect cannot become resistant to its own biology, and you will win this battle every time. For example, use a bait for ants that you know they will carry back to their nest and feed to their young. This won’t kill the ants right away, but if you are patient you will find that the whole mound will be dead in a week or two.
— Use and encourage beneficial, natural controls. Plant composite flowers like daisies that have many small flowers packed tightly together to attract beneficial insects, or put out bird feeders that attract insect-eating birds.
— Don’t expect total eradication of pests. There are always new pests ready to step in.
Beneficial insects are easy to attract and keep around if you provide them with the food and shelter they need. If you are attracting beneficial insects, it is very important that that you use no pesticides in your garden, or you will inadvertently kill the good insects along with the bad. Many beneficial insects are very small and you may never know they are in your garden; others are larger and always seem to be on patrol.
A general approach to attracting beneficial insects is to plant a few known host plants in and around your garden. Some favorites are dill, carrots, calendulas, zinnias, sunflowers, basil, thyme, sage, asters, yarrow, marigolds, parsley, and artemisia. Many other composite flowers that attract butterflies attract beneficial insects too. It is also a good idea to provide a water source, such as a birdbath or a saucer of water placed on the ground. Finally, try to control stray weeds around your garden that might harbor pest insects.
This section will help you address specific pest problems. It lists the most common beneficial insects, the insects they control, and what they need to take up permanent residence in your garden.
ADULTS: 
(1.5 mm) inch long. Looks like a very small wasp, but a very delicate one.
LARVAE OR CATERPILLARS: Small, ⅛-inch orange maggot.
BENEFIT: Larvae eats more than sixty species of aphids.
RANGE: Throughout North America.
HOW TO ATTRACT: Landscape with plants that have plenty of pollen and nectar in areas protected from the wind. Provide a water source.
NOTES: Available commercially. Adults are active mostly at night.
ADULTS: ½ to 1⅜ inches long (12 to 33 mm). True bugs, or insects in the order Hemiptera, that are flattened with elongated heads. The beak is usually curved and tucks under head into a groove. Some species are brightly colored, others not.
NYMPHS: Similar to adults but smaller.
BENEFIT: Predator of many common pest species of insects, including flies and caterpillars.
RANGE: Throughout North America.
HOW TO ATTRACT: Assassin bugs are found naturally in most gardens where insects are present.
ADULTS: ⅛ to ¼ inch (3 to 6 mm) long. Fast-moving true bug with large eyes and minute black spots on head and thorax.
NYMPHS: Similar to adults, but smaller and wingless.
BENEFIT: Eats aphids, leafhoppers, plant bugs, spider mites, and small caterpillars.
RANGE: Western North America.
HOW TO ATTRACT: Big-eyed bugs are found mostly in field crops and orchards. They like to lay their eggs on soybeans, pigweed, and goldenrod. Small weedy areas next to crops make a great shelter for these bugs.
ADULTS: 1/8 to ½ inch (2.4 to 12 mm) long. Black or brown with thin thread waists.
LARVAE OR CATERPILLARS: Very small, cream-colored grubs that feed on other insects.
BENEFIT: Braconid wasps lay eggs that parasitize and kill aphids, armyworms, cabbageworms, codling moths, corn borers, elm bark beetles, hornworms, and some flies.
RANGE: Throughout North America.
HOW TO ATTRACT: Plant nectar plants such as dill, parsley, and yarrow for the adults. Provide a water source.
NOTES: Available commercially.
ADULTS: ½ to 1 inch (12 to 24 mm) long. Plump, with black and yellow striping on thorax, black face and head, smoky-color wings, hairy body. Pollen basket on hind legs.
LARVAE: White grubs.
BENEFIT: Pollinators.
RANGE: Throughout North America.
HOW TO ATTRACT: Supply plenty of pollen and nectar flowers. Bumblebees are naturally occurring in most gardens.
ADULTS: ⅜ to ½ inch (9 to 12 mm) long. Fast-moving true bug with elongated gray or brown body.
NYMPHS: Similar to adults but smaller and wingless.
BENEFIT: Nymphs are predators of aphids, leafhoppers, plant bugs, and thrips.
RANGE: Throughout North America.
HOW TO ATTRACT: Damsel bugs love alfalfa.
ADULTS: ¾ to 1 inch (18 to 24 mm) long. Beetles are black or brown in color. Head, thorax, and abdomen are well defined, and on many, iridescent.
LARVAE: Dark brown or black grubs that have ten segments. Body tapers toward the abdomen tip.
BENEFIT: Large group of beetles that are predators of cabbageworms, cutworms, slugs, snails, and most ground insects. Larvae are also predators with giant appetites.
RANGE: Throughout North America.
HOW TO ATTRACT: These beetles are naturally occurring in most gardens. Provide shelter for them by planting permanent beds or adding stones near the garden they can crawl under. Paths throughout the garden that are planted with white clover, sod, or a ground cover are suitable to shelter as well.
ADULTS: Female worker bees are ⅜ to ⅝ inch (9 to 15 mm) long. Males are a bit larger with larger eyes. Gold- and black-striped hairy body; translucent wings.
LARVAE: White grubs found in their hives.
BENEFIT: Pollinators.
RANGE: Worldwide.
HOW TO ATTRACT: Provide pollen and nectar plants.
Provide a water source.
NOTES: Average size of hive is 60,000 to 80,000 bees.
ADULTS: ½ to ⅝ inch (12 to 15 mm) long. Resemble honeybees when hovering over flowers. Abdomen flattened with yellow or white and black striping. Two translucent wings.
BENEFIT: Larvae feed on aphids, mealybugs, and other small insects.
RANGE: Throughout North America.
HOW TO ATTRACT: Landscape with plants that have a lot of pollen and nectar. Plant yarrow or composite flowers among garden plants to attract the adults.
ADULTS: ⅛ to 3 inches (3 to 72 mm) long. Take many colors but the most common are brown and black. Bodies are slender. Females often have a very long ovipositor that people may misperceive as a stinger. All have long antennae that are in constant motion.
LARVAE: Small grubs with tapered ends.
BENEFIT: Adults feed on many different types of insects and spiders. Adult females parasitize caterpillars and then lay eggs on the caterpillars that in turn feed on the caterpillars.
RANGE: Throughout North America.
HOW TO ATTRACT: Landscape with plants rich in pollen and nectar. Females especially like flowering clover. Provide a water source.
ADULTS: ½ to ¾ inch (12 to 18 mm) long. Two types are most common: green-colored lacewings and brown-colored lacewings. Large, netlike transparent wings form a tent over the abdomen when at rest. Head is small with large eyes.
LARVAE: Spindle-shaped body is usually mottled yellow or brown.
BENEFIT: Both larvae and adults are predators of aphids, mealybugs, and many other small soft insects. Larva called the “aphid lion.”
RANGE: Throughout North America.
HOW TO ATTRACT: Allow some flowering composite plants—carrots and dill, for example—to grow and flower in the garden. Plant flowers that have lots of pollen and nectar, and provide a water source.
NOTES: Sold commercially. Eggs laid on long stalks on underside of leaves.
ADULTS: to ⅜ inch (1.5 to 9 mm) long. Bodies are round and often spotted. Most are shiny red, orange, or yellow in color with black markings.
LARVAE: Spindle-shaped body is covered with spines, bright spots, and bands.
BENEFIT: Both larvae and adults feed on aphids, scales, mealybugs, and small insects.
RANGE: Worldwide.
HOW TO ATTRACT: Landscape with plants rich in pollen and nectar-producing flowers. Plant carrots, yarrow, or another composite flower in the garden and allow to bloom.
NOTES: Available commercially. Mexican bean beetles are also a member of this group and are not considered beneficial.
ADULTS: ⅓ inch (8 to 9 mm) long. Body is oval, wing covers are black. Head and tip of abdomen is coral-colored.
LARVAE: Cream-colored larvae with lots of long, waxy filaments all over body.
BENEFIT: Both larvae and adults feed on mealybugs.
RANGE: Western coastal regions of North America.
HOW TO ATTRACT: Occur naturally in native areas when mealybugs are present. NOTES: Sold commercially.
ADULTS: ¼ inch (6 mm) long. Quick-moving true bugs with a black and white pattern.
NYMPHS: Similar to adults but wingless. Nymphs go through many color changes—from yellow to orange to brown—before reaching their adult coloration.
BENEFIT: Predators of thrips, spider mites, small caterpillars, immature leafhoppers, and insect eggs.
RANGE: Throughout North America.
HOW TO ATTRACT: Plant goldenrod, daisies, yarrow, alfalfa, and other flowering plants that produce pollen and nectar.
NOTES: Sold commercially. Average release rate is one pirate bug for up to five plants.
ADULTS: 
inch to several inches (.96 to 72 mm) long for beneficial nematodes. Many others are microscopic. Over 10,000 species, with some categorized as pests.
BENEFIT: Parasitic nematodes attack and parasitize many soil-dwelling immature insects such as fleas, root weevils, crown borers, corn rootworms, and grubs of many beetle species.
RANGE: Throughout North America.
HOW TO ATTRACT: Naturally occurring in moist soils. To increase populations, purchase commercially sold nematodes and add to moist soil.
NOTES: Sold commercially.
ADULTS: 2 to 2½ inches (48 to 60 mm) long. Large green or tan insects with big compound eyes. Wings extend beyond abdomen. Large front legs to catch insects.
NYMPHS: Similar to adults but smaller.
BENEFIT: Predators of almost all insects. Unfortunately, these indiscriminate eaters will devour beneficial insects as well.
RANGE: Southern and eastern United States into Ontario. Another species of mantis lives in the West.
HOW TO ATTRACT: Provide permanent plantings for mantises to overwinter near the garden.
NOTES: Sold commercially.
ADULTS: Minute fast-moving mites. Colors range from beige to reddish brown.
NYMPHS: Similar to adults but smaller.
BENEFIT: Predators of spider mites, European red mites, citrus red mites, other mite species, and thrips.
RANGE: Throughout North America.
HOW TO ATTRACT: Naturally occurring populations. To maintain native species of predatory mites or increase their numbers, sprinkle pollen from ice plants, cattails, or dandelions on plants.
NOTES: Sold commercially.
ADULTS: ½ to 1 inch (12 to 24 mm) long. Dark insects with pronounced head that can be raised, unlike most insects. Wings are transparent and have netlike veining. Wings are folded, tentlike, when at rest over the body.
LARVAE: Black bodies; they look very similar to beetle larvae.
BENEFIT: Both the larvae and adults are active predators on other insects such as aphids and caterpillars.
RANGE: Mostly in the western United States and British Columbia.
HOW TO ATTRACT: Occur naturally in native areas; always looking for prey.
ADULTS: ⅓ to ½ inch (8 to 12 mm) long. Long, slender beetles that are flattened. Wing covers are leathery and appear downy. Pronounced head and thorax.
LARVAE: Dark, flattened grubs that are covered with hairs.
BENEFIT: Both larvae and adults are predators of aphids, cucumber beetles, corn rootworms, grasshopper eggs, caterpillars, and beetle larvae.
RANGE: Throughout North America.
HOW TO ATTRACT: To attract adults, plant goldenrod, milkweed, hydrangeas, or catnip. Larvae overwinter in the soil, so keep some permanent plantings for the beetles to have a place to lay their eggs.
ADULTS: ½ inch (12 mm) long. True bugs that are grayish brown and shield-shaped. Shoulders of thorax come to sharp points.
NYMPHS: Similar to adults but wingless.
BENEFIT: Predator of caterpillars, grubs, armyworms, sawflies, and Mexican bean beetle larvae.
RANGE: Throughout North America.
HOW TO ATTRACT: Provide shelter of permanent perennial plants near the garden.
ADULTS: ⅓ to ½ inch (8 to 12 mm) long. Gray, brown, or black. Look like big hairy houseflies with mottled colored bodies.
LARVAE: Cream to whitish-color maggots.
BENEFIT: Females deposit eggs that parasitize and kill caterpillars of many pest species, such as cabbage loopers, gypsy moths, armyworms, and tent caterpillars.
RANGE: Throughout North America.
HOW TO ATTRACT: Adult flies feed on flower nectar. Plant such flowers as dill, parsley, and sweet clover. Watch for caterpillars with white eggs attached to them, and don’t kill the caterpillars. These eggs will eventually turn into more tachinid flies.
ADULTS: ½ to ¾ inch (12 to 18 mm) long. Bright-colored and patterned, long-legged beetle.
LARVAE: S-shaped, segmented grubs have a hump on the fifth segment. The hump is covered with strong hooks.
BENEFIT: Both the larvae and the adults feed on other insect species.
RANGE: Throughout North America.
HOW TO ATTRACT: Provide shelter by planting permanent perennial plants near the garden.
NOTES: Beetles are often drawn to lights at night.
You’ve determined that you need the help of beneficial insects and you would like to purchase some for your garden. How do you find the right supplier?
You can purchase beneficial insects in several different ways. Many nurseries and home centers now carry them during the spring and summer months. They usually have adult ladybugs and parasitic nematodes, and sometimes even praying mantis eggs. The selection varies widely.
Your local nursery is the best source for parasitic nematodes. They come suspended in a clay base for retail sale; the nematodes last longer on the shelf than live insects do. Still, always check the expiration date on the package to make sure the nematodes are not left over from last year.
Some nurseries don’t carry live insects at all, but instead sell you an order form that you mail in. The insects then arrive at your home in about a week.
Your best bet for buying live insects is to order them directly from the supplier. Usually you can save yourself some money. Check the buying guide at the back of this book for supplier names and addresses.
Decide which insects you are interested in buying, and then do some calling around. Many suppliers have a toll-free number; use it. Be sure to ask a few questions. Here are some examples:
— How much do the insects cost, and how many do you get for the price? Prices vary.
— If you are not sure about a certain insect surviving in your area, ask if it will survive in your climate and for how long. The supplier may know of another insect that will do the job better.
— Does the supplier guarantee the insects will be delivered live? Things can happen in shipment. Look for a return policy in case they arrive dead.
— In what form will the insects arrive? Eggs, pupae, adults?
— Will instructions be included in the package concerning handling, rearing of eggs or pupae, and the best way to release the insects?
— Is this a good time of year to release the insects into the garden or is there a better time?
— Is the supplier a member of the Association of Natural Biocontrol Producers? Members are generally reputable and will try hard to make sure their customers are satisfied.
Once the insects arrive at your home, follow the instructions that come with them precisely. Some live insect adults are shipped on ice to keep them cool and slow down their systems. They should start moving around in about thirty minutes after being taken off the ice.
It is very discouraging to release ladybugs or other adult beneficial insects, only to see them all fly away. Try this trick to keep them around long enough to eat some of your pests (of course, do this only if there are no specific releasing instructions from the supplier): Wet the pest-infested plants well and release the insects on them in the evening. Generally, ladybugs are thirsty when released and immediately look for water. If the foliage is wet, they may stop for a drink and then decide to stay the night. In the morning, they will be right where you want them, ready to eat the pests you want to get rid of.
You can easily make your own insect-killing sprays and repellents, many of them with ingredients that come straight out of your kitchen cupboard or medicine chest. These sprays and repellents are just as effective and a lot less toxic to the environment than those that are available commercially. In fact, many are completely nontoxic.
Remember, as with any spray, always test these first. Spray a couple of leaves and then check the leaves in a day or two for burning. If there isn’t any burning, then it is safe to spray the whole plant.
Horticultural oil sprays have been commercially available for quite some time. They work by smothering the insects and mites they come in contact with, thus preventing several disease-causing pests from taking up residency on such favored plants as roses, hydrangeas, phlox, and zinnias. When oil is mixed with other ingredients it can also kill fungal diseases that are present on the plant.
Aphids, scale insects, and other insects that stay on the plant are particularly susceptible to oil. In contrast, grasshoppers and insects that take a bite and leave quickly are not usually affected. When using any spray, remember that it will kill beneficial insects as well as pests and spray only when you are sure the pests are present. Also, oils can burn sensitive plants, especially during hot summer months, so before spraying an entire plant always spray a few leaves and then check the next day for burning. Cauliflower, red cabbage, and squash are very susceptible to oil burning. Special so-called summer oils are commercially available. They are very light and evaporate off the plant quickly.
For best results, spray both the upper and undersides of the leaves when the temperature is between 40 and 90 degrees.
If you make your own oil spray, you can tailor it to your specific needs. Here are a few simple recipes.
Step 1: Make the oil mixture
1 cup vegetable oil (safflower, corn, soybean, or canola)
1 tablespoon dishwashing liquid
Place oil and water in a jar or empty plastic ketchup bottle. Squeezable ketchup bottles make for easy pouring and measuring. Leftovers can be kept in these containers for later use.
Step 2: Make the spray
1 tablespoon oil mixture from Step 1 (for delicate plants reduce the oil mixture to 1 teaspoon)
2 cups water
Place the solution in sprayer or spray bottle, and spray plant. Because oil and water don’t mix well, shake sprayer bottle periodically while treating to keep the solution well mixed. Repeat treatment in seven to ten days if necessary.
Alcohol oil spray
To increase the effectiveness of the basic oil spray, add some isopropyl alcohol to the mixture. An alcohol and water solution is lethal to many insects.
1 cup alcohol
1 teaspoon vegetable oil
1 quart water
Mix ingredients together and place in spray bottle. Spray on pest-infested plants as necessary.
Garlic is a bug-busting wonder. It can repel and—when mixed with oil—kill some of the biggest garden pests, including aphids, cabbage moths, cabbage loopers, earwigs, leafhoppers, mosquitoes, and whiteflies. Besides working on insects, garlic also kills the harmful fungi that cause plant diseases like powdery mildew, rust, and gray mold. (See this page for details.)
Step 1: Make the garlic oil
1 whole head of garlic, minced (or run through a garlic press)
1 cup vegetable oil
Mix garlic and oil together. Let the mixture sit for up to two days in the refrigerator. (Fresh garlic and oil will turn rancid if not refrigerated.) The oil should have a strong garlic smell when ready. If it doesn’t, add more garlic and let sit another day. Strain out garlic.
Step 2: Make the spray
2 to 3 teaspoons garlic oil (see Step 1)
1 quart water
2 to 3 drops dishwashing liquid
Spray plants when insects appear or at first signs of mildew. Repeat treatment in two weeks if necessary.
Dormant tree oil spray
Use dormant tree oil spray to protect your stone fruit trees—apricots, peaches, and plums, for example—against both insects and fungus. This is a two-part procedure for dormant trees only. First, spray the tree with copper sulfate. Copper sulfate is available at all nurseries. Wait a few days for the copper sulfate to dry completely. Second, make the following mixture.
1 gallon water
12 tablespoons canola or safflower oil
1 teaspoon dishwashing liquid
Pour into sprayer and spray entire tree.
Here are a few other insect-killing sprays that can be made with ordinary household items.
Basic soap spray
Soap spray is probably the most common of all homemade sprays. It works best on soft-bodied insects such as mites, aphids, whiteflies, thrips, and many other insects in their immature stages. It works by penetrating the cell membranes and causing the insects to dry out. Soap is less effective on fast-moving insects, because the spray must come into contact with them. With insects that have very tough coverings, you may need additional soap spray treatments to kill them completely. Soap is safe on edible vegetables and usually leaves no residue on plants.
2 tablespoons dishwashing liquid
1 gallon warm water
Mix and use as a spray. Repeat as necessary.
Extra-easy soap spray
Place a bar of soap in the toe of an old pantyhose leg. Tie the pantyhose to the handle of watering can, so the bar of soap hangs inside. Fill the can with warm water and swish the bar around for a few seconds, or let sit for a minute. Use this soapy water on your plants. Experiment with the time you let the bar sit in the water. Start with a few seconds and increase the time until you achieve the right concentration to kill the pests—different soaps may need different lengths of time to dissolve. When finished watering, just let the soap in the pantyhose hang inside the can until dry. Repeat as necessary.
Other ingredients may be added to the basic soap spray for greater effectiveness.
— Add sulfur to kill mites, fungi, and insects; see package directions for amounts.
— Add 1 or 2 tablespoons of baking soda to the basic soap recipe and you will kill fungi as well as insects.
— Add citrus oils (1 or 2 teaspoons) for extra penetrating power.
— The caffeine in coffee and tea has been shown to disrupt the behavior of many insects. When added to an insecticide, coffee and tea increase its effectiveness. Instead of pouring that stale old brew out when you make a new pot, save it and replace some of the water in your favorite soap recipe with a cup or two.
— Finally, peppermint mixed with soap is very effective at cutting through the waxy defenses of many insects. Mix 1 or 2 teaspoons of peppermint extract into your soap recipe, or use a commercially purchased liquid peppermint soap to make your soap spray.
Lemon spray
Here’s one more use for the handy lemon: it can be made into quite an effective insect spray. The chemical limonene, found in lemon peels, is an effective killing agent. Whiteflies and soft-bodied insects are killed quickly with this spray. It can even get rid of fleas on your pet. However, just like people, pets can be allergic to lemons. To use as a flea killer, sponge mixture on pet. Then leave it on, or rinse it off. If shaking or signs of an allergic reaction start, shampoo pet immediately. If symptoms persist, call your veterinarian.
Peels of 2 large or 4 small lemons
1 quart water
Boil the lemon peels for 10 minutes. Cool. Take out peels, and place solution in a spray bottle.
Ammonia spray for mites
Mites can be a big problem for many plant species. Those of us who grow fuchsias know that mites on these beautiful plants can be hard to fight. This spray not only kills the mites but also acts as a mild fertilizer.
2½ gallons water
1 teaspoon dishwashing liquid
3 teaspoons ammonia
Mix solution and pour into spray bottle. Treat plants every five days for three weeks to get rid of mites.
Diatomaceous earth (DE) is the fossilized shells of microscopic sea diatoms, which act like tiny razor blades on insects. When an insect comes in contact with DE it is injured and eventually dries out and dies. DE comes in two grades, garden grade and swimming-pool grade. When treating plants, be sure to use only garden-grade DE. The swimming-pool grade is much coarser and is not intended for garden use.
Dusting plants with DE prevents many chewing and sucking insects from harming them. Mist the plant with water first and then lightly dust on the DE. The mist helps hold the DE in place. Dust as much of the plant as possible. A note of caution: always wear a dust mask when using any fine dusting material.
If you find dusting too tedious, you can make a DE spray.
Diatomaceous earth spray
1 quart water
1 teaspoon liquid insecticidal soap or dishwashing liquid
¾ pound DE
Mix ingredients together and place in a 5-gallon sprayer. Add more water to fill. Shake to mix. Spray plants.
You can use DE in other ways as well. To stop snail and slug damage to plants, ring the plants with DE. This works to prevent damage from crawling caterpillars on young trees as well.
Sowbugs also are very vulnerable to DE. Make a paste from DE and water and spread it on the trucks of trees. Again, this will control caterpillars as well.
Sprinkle DE around seedlings to help protect them from hungry grubs and maggots. Also, if you dust seeds with DE either before planting or when they are on the ground, they will stand a better chance against weevils and other seed-eating insects.
DE washes off with water. Reapply after rainstorms or overhead-watering for maximum effectiveness.
Our grandparents knew that dusting a plant with flour was a good way to kill many pest insects. The flour dust turns into a sticky substance that can hold a pest like a sticky trap. Or the insects eat it, and the flour stops up their digestive tracts. To get more flour on the plant try spraying it on.
2 to 4 tablespoons wheat or potato flour
½ teaspoon dishwashing liquid
1 quart water
Mix ingredients well and place in spray bottle. Spray on plant leaves and stems.
These common foods and plants repel many types of insects; some are all-purpose, others are insect-specific.
Anise is a good repellent for a variety of pests. Many gardeners report less of a problem with aphids, fleas, and cabbage pests when anise is planted nearby.
Catnip deters many pests, such as Colorado potato beetles, darkling beetles, flea beetles, Japanese beetles, squash bugs, weevils, and probably the biggest pest of all, ants. However, when planting catnip understand that your garden will be a favorite stop for every cat in the neighborhood.
Garlic has been known to repel not only insects but animals as well. Plant edible garlic between vegetable rows or next to roses to repel aphids and many other insects. Garlic powder can be dusted directly on the plant, or garlic can be made into a spray for a more concentrated dose. Try one of the following garlic sprays.
6 cloves garlic
½ onion
1 tablespoon cayenne pepper
1 tablespoon dishwashing liquid
1 quart water
Put first four ingredients into a blender, add some of the water, and blend until smooth. Pour mixture into a jar and add the rest of the water. Let steep for 24 hours. Strain, then pour the liquid into a spray bottle. Treat plants. Keep extra spray in refrigerator for up to 2 weeks. Treat again if necessary.
Easy garlic spray
½ cup finely chopped garlic cloves
(onion or chives may be substituted for garlic)
1 pint water
Mix garlic and water well. Let sit for about an hour. Strain out garlic and pour into spray bottle. Treat plants with fine mist.
Geraniums have long been noted for their resistance to pests. It is thought that their often pungent odor repels insects. Rose growers have noted that when they plant white geraniums among and around their rose bushes they have fewer problems with Japanese beetles. Gardeners have noted fewer pests when scented geraniums are planted near tomatoes. Make a geranium spray to use on plants to repel many kinds of insects. (This recipe may also be made with marigolds or any pungent plant, including garlic.)
Geranium repellent spray
Combine equal amounts of geraniums and water in a blender, and whirl until smooth. Strain mixture through a cheesecloth or fine strainer. To use, dilute the geranium liquid at the rate of 1 teaspoon to 2 cups water. Spray where needed.
Many people claim that hot pepper plants provide some repellent qualities when planted in among other plants. Some say hot peppers keep down the occurrence of black spot. Try making your own hot pepper spray. Just remember to wash off any vegetables you spray with this mixture before eating them.
Hot pepper repellent spray
3 to 4 hot peppers (serrano, habanero, or other very hot pepper), chopped
1 quart boiling water
1 quart cold water
2 drops dishwashing liquid (optional)
Drop peppers into a pot of boiling water. Remove pot from the stove and let steep for 24 hours. Discard peppers. Add the cold water to dilute the pepper solution. Add the dishwashing liquid to help the spray stick to the plant. Be sure to check a small spot on your plant for burning before spraying the entire plant.
Hot peppers that have been made into powders like chili powder, cayenne pepper, black pepper, and red pepper can also be made into pepper sprays or used alone. The ingredient that makes them hot, capsaicin, is known to repel lots of insects, from ants to root maggots. Ring vulnerable seedlings of onions, cabbages, carrots, or other plants with hot pepper powder to protect them. Dust it on plants to control caterpillars, too. It’s a good idea to wear a dust mask when using hot pepper powder. And keep it away from pets. Of course, if your pets are bothering your garden, this just might keep them out! Generally dogs don’t like the smell of pepper.
The beautiful marigold flower provides a garden not only with great color but with insect-repelling qualities as well. Some of the pests it repels are Mexican bean beetles, asparagus beetles, tomato hornworms, and many cabbage pests. Gardeners plant marigolds next to cabbages, potatoes, and tomatoes. Scientists have shown that, planted within a three-foot radius of vegetables, marigolds actually keep nematodes in the soil away as well. You can make an insect-repellent spray with marigolds by following the recipe for the geranium spray on this page, but substitute marigolds for geraniums.
Nasturtiums planted among other plants have been shown to repel many different kinds of insects, such as aphids, cabbage loopers, squash bugs, and whiteflies. One attractive way to do this is to plant nasturtiums with vining crops such as squash, cucumbers, and melons. Potatoes planted next to nasturtiums are said to have fewer problems with potato beetles. An extra bonus to using nasturtiums is that the flowers are edible! Try adding them to your next tossed salad.
Petunias look pretty in your garden, but studies have shown they also actually repel a number of pests, including Mexican bean beetles, potato bugs, and squash bugs.
Rosemary is known to repel Mexican bean beetles, cabbage moths, and carrot flies.
Tansy has been known for quite some time to be a great repellent for many different types of insect pests. Many gardeners swear that tansy planted in a ring around their fruit trees helps to repel fruit flies. Tansy is also said to repel Japanese beetles, ants, aphids, cabbage loopers, squash bugs, and beetles.
Perhaps you have noticed that very few pests bother tomatoes. Tomato plants contain alkaloids that repel many insects, including cabbage pests, asparagus and flea beetles, and whiteflies. Often tomatoes are planted with beans, cabbage, onions, and peas to protect these crops from pests. Try making this solution from tomato leaves to spray on other plants to repel pests.
2 cups chopped tomato leaves
1 quart water
½ teaspoon dishwashing liquid
Combine the tomato leaves and water in a saucepan. Heat to simmering, then turn off the heat. Let mixture steep until cool. Strain the leaves from the water and add soap to the water. Place solution in sprayer or spray bottle and use where needed. The solution should have a “tomatoey” smell. Spray where needed.
Try using these natural repellents for specific pests.
— Banana peels placed around roses and other plants plagued by aphids will make the pests disappear. How banana peels repel aphids is still unclear, but it seems to work. Keep putting the peels around the base of the plants as long as aphids are a problem. As a bonus, the potassium in the peels stimulates larger blooms.
— Citrus rinds have a chemical in them that deters corn earworms. To make a solution of citrus rinds, chop up the rinds of 2 to 4 fruits. Place them in a container with a quart of hot water. Let sit overnight. Strain out rinds and spray on affected plants. Another easy lemon spray is on this page.
— Lemongrass repels wasps. Wasps can be quite annoying at a picnic or barbecue. Next time, take along some lemongrass and lay it on the picnic table or put it in a vase. The wasps will stay away.
— Peppermint tea sprayed onto plants has been shown to repel Colorado potato beetles. Steep two peppermint tea bags or about ¼ cup fresh chopped mint leaves in a quart of very hot water for thirty minutes. Let the tea cool, then strain and spray on plants. Experiment with the strength of the spray. And try it on other plants for other pest problems. Research shows that mint may be a good all-purpose repellent.
— Old tires used as planters repel squash and cucumber beetles. In addition, many gardeners have had good success planting heat-loving plants inside old tires.
— Wood ashes are a way to get rid of cucumber beetles. Make a spray out of wood ashes by mixing ½ cup ashes in 2 gallons of water. Put solution in watering can and water plants. Note that if mildew or other fungi are a problem, overhead watering is not advised. Furthermore, ashes are very alkaline, so use sparingly on alkaline soils.
By planting certain crops together, you will repel insects on your favored crop.
— Borage repels Japanese beetles on potatoes. Borage also is a great plant for attracting many beneficial insects.
— Chrysanthemums planted in soils that have nematode problems have reduced the populations of nematodes.
— Dead nettle or henbit, a member of the mint family, is believed to repel potato bugs. Just plant it among your other plants. Many gardeners report that dead nettle also improves the growth and flavor of many vegetables when planted together with them.
— Dill planted in the garden is a great general repellent for aphids and spider mites.
— Fennel is said to repel aphids in the garden when planted near susceptible plants.
— Green beans planted with eggplants repel Colorado potato beetles.
— Leeks planted with carrots repel carrot flies.
— Mint planted next to broccoli and cauliflower is said to repel cabbage loopers, which love the taste of nice fresh heads. Although it’s a wonderful garden addition, mint can become invasive. Here’s an easy solution: Cut the top and bottom rounds from a large coffee can. Then “plant” the can in the garden with the open lip at soil level, and plant the mint inside the buried can.
— Onions planted with cabbage, carrot, corn, potatoes, and tomatoes show some ability to repel several pest insects, including potato beetles and carrot flies.
— Parsley planted with carrots repels carrot worms. As an added benefit, you can harvest the parsley to use fresh or dried.
— Potatoes planted near beans, cabbage, cauliflower, and corn have been shown to repel attacks from Mexican bean beetles.
— Radishes planted around cucumbers, cabbages, melons, and other vegetables are said to repel many insects, including cucumber beetles, root flies, and vine borers.
— Sage repels cabbage flies and root maggots. When planting members of the cabbage family like broccoli or cauliflower, try planting some sage around them. Sage works well to repel pest insects from carrots, too.
— Thyme has been shown to repel cabbage loopers and whiteflies when planted near cabbage plants.
Insect traps can go a long way in keeping numbers of certain insects down and preventing plant damage. The idea is to attract the insects to something they like and keep them off what you like. Many different kinds of traps can help you grow beautiful plants and vegetables for yourself, not for the pests.
With one of us an entomologist and the other a gardener, we have heard about every kind of insect trap known to humankind. Many of our readers have kindly sent us their tried-and-true insect-trap ideas. Some of those they’ve told us about use bait to lure the insects, others are more inventive. We hope one helps you solve your insect problem.
Adult aphids are attracted to yellow when migrating to other plants. It is thought that the insects perceive yellow as a patch of bright foliage. Make yellow sticky traps from heavy paper (see this page for details), purchase yellow sticky traps, or fill yellow buckets with water to attract and drown them.
Apple maggots and cherry fruit flies like red sticky sphere-shaped traps; walnut husk flies like green-colored ones. Make these traps by painting old balls or lightbulbs and then spraying them with spray adhesive. Hang them. When they are covered with flies throw them away. Or place red balls inside a plastic sandwich bag, and use a twist-tie to close the bag tightly over the ball. Now coat the plastic bag with a sticky substance, such as Tanglefoot. Hang a couple in each tree. When the ball is covered with insects, merely take the plastic off, discard, and repeat with another plastic bag. You can also trap apple maggots in jars or cans filled with a solution made of 1 part molasses and 9 parts water. Hang jars or cans in trees. The insects are attracted to the solution, fall in the cans, and drown.
To make a trap for beetles, cut the top off a 1-gallon plastic milk jug, leaving the handle on. Fill the jug with water, and add a squirt of dishwashing liquid. When you see beetles feeding on your favorite plants, just slip the jug under the plant or branch and give the branch a quick tap. The beetles will fall into the jug and drown. Try this early in the morning when fast-moving beetles are still cold. This is a great method for trapping Japanese beetles because the creatures play dead when disturbed and don’t try to fly away.
To catch clothes moths, make a yellow sticky trap (see this page) but put the adhesive on one side only. Then place some fish meal (fish food, purchased at a pet store) in the middle of the trap. Now place the trap on the floor of your closet. Another way to do this is with duct tape. Place the tape sticky side up on a piece of cardboard, and then put some fish meal in the center. Try the yellow trap and then the gray duct tape one to see if the color makes a difference. (Some say it does, others say it doesn’t.) This trap will also catch dermestid beetles, silverfish, booklice, roaches, and crickets.
Wrap the trunk of your tree with corrugated paper or cardboard. This traps the small caterpillars before they climb up the tree to feed on its leaves. Replace paper periodically.
To trap cucumber beetles, set out cantaloupe or cucumber rinds on a piece of newspaper. When you see beetles on the rinds, quickly crumble the paper to catch the beetles inside. Then dunk the paper with rinds and beetles in a large bucket of soapy water. Later, throw paper, rinds, and dead beetles right into the compost pile.
For cutworms in the soil, mix 1 gallon water with 3 tablespoons dishwashing liquid. Pour on trouble spot. The solution will bring the worms to the surface where you can invite birds to eat them or dispose of them yourself. For cutworms in the garden, lay boards around areas that have cutworms. Check under the boards during the day and discard coiled cutworms.
Here are two methods to catch earwigs. First: Lay six- to eight-inch pieces of old garden hose in places where earwigs are a problem. Then leave them there for a day or so. After that, shake the hose pieces over a bucket of soapy water to dislodge the earwigs from inside. Repeat. Second: Place a damp rolled-up newspaper in the garden in the evening. Pick up the paper with earwigs in the morning.
Flea beetles are attracted to the color white. Try making white sticky traps. (See this page for details.) Flea beetles are also attracted to beer. Place a wide-mouthed jar containing one or two inches of beer in your garden. The beetles will fly in and drown.
To trap flies, mix 2 cups water with ½ cup sugar and ½ cup vinegar or apple cider vinegar. Place the solution in an empty two-liter soda bottle and set it outside. The flies will fly into the bottle and drown. To keep flies out of your house, take a large clear plastic bag and drop a small piece of aluminum foil in it. Then fill bag with water, tie it closed, and hang it over a window or doorway. Flies will no longer enter. Why? We aren’t sure!
Fruit flies are attracted to the color yellow, so make yellow traps to catch them. To make a yellow sticky trap, glue yellow paper to a piece of cardboard. Spray the paper with adhesive. Then hang or stake the paper outside to catch flies in the garden. A second way to make a sticky trap is to spray a piece of yellow plastic with cooking oil or rub petroleum jelly on it before hanging. Finally, you can use a yellow plastic bucket to make a lure. Just fill the bucket halfway with water and set it in the garden. Flies will be attracted to it and fall in and drown.
To trap grasshoppers, bury a sixteen-ounce coffee can up to its lip in or near your garden. Then fill the can almost to the top with a solution made up of 1 part molasses and 9 parts water. Grasshoppers are attracted to it and fall in and drown. Several other pest insects will be attracted as well.
Adult moths usually lay their eggs on tree trunks. When the caterpillars hatch, they crawl up the tree to feed. To catch them before they do, make a collar out of burlap. Take about two feet of burlap and tape it onto the trunk about two feet up off the ground. The burlap must wrap all around the trunk, like a sash, with a bit extra at the ends to overlap. Tie a string or cord around the middle of the sash. Then remove the tape and fold the upper portion down over the cord and lower portion. When caterpillars try to crawl up the tree, they will get caught in the fold. Check and remove caterpillars daily.
Hornworms are hard to spot because they blend in with the surrounding plants. Try spraying your plants with cold water. The hornworms will move about, making them easier to see and hand-pick.
Like fruit flies, leafhoppers and leaf miners are attracted to yellow sticky traps. (See above, under “Fruit flies,” for details on making traps.)
Use the carnivorous sundew plant as a natural trap for mosquitoes. The plant has sticky stems. Hang the plant outside and it will catch many mosquitoes.
Rose chafers are attracted to white, so make white sticky traps to catch them. Glue white paper to a piece of cardboard, then spray with adhesive. Now stake the paper traps among your rose bushes. (You can also purchase white sticky traps.)
To trap silverfish, take a small glass jar—a baby food jar, for example—and wrap the outside of it with masking tape (the sticky side facing in, sticking to the jar). Then put a little wheat flour into the jar as bait. Place jars under sinks or anywhere silverfish are present. The silverfish can climb the rough tape to get into the jar, but they can’t climb back out on the slippery glass. Check often.
Here are two ways to trap slugs and snails. First: Lay a board out along the edges of your garden, propping one corner up just a bit. Slugs and snails will crawl under the board during the day seeking shade. Pick up the board and dispose of the creatures. Second: Place hollowed-out orange or melon rinds, cut side down, in your garden in the evenings. In the morning, just pick up the rinds and throw the slugs and snails away.
To trap sowbugs or pillbugs, simply place cabbage or potato peels under a clay flowerpot in your garden. Every few days, harvest the bugs that have congregated under the pot. Then either place them elsewhere in your yard, such as the compost pile where they can work as decomposers, or dump them into a bucket of soapy water.
Tarnished plant bugs are attracted to the color white, just as rose chafers are. Try making white sticky traps for them too.
Thrips are attracted to blue and sometimes to yellow. Make sticky traps to catch them.
Make a wasp trap from an empty two-liter soda bottle. The simplest method is to pour fruit punch or flat soda into the bottle (don’t fill it more than halfway), leave the top off, and set the bottle outside. Wasps fly into the bottle, get caught in the liquid, and drown. But remember: wasps are actually beneficial insects and control many unwanted insects.
Whiteflies are attracted to yellow sticky traps. (See this page for details.)
Trap wireworms in pieces of cut fresh potatoes scattered around the garden. Check potatoes daily for the worms and replace the potatoes with fresh ones as needed. Drop infested potatoes in a bucket of soapy water, then compost.
Many fruit tree pests—like cherry fruit flies, green fig beetles (June beetles), and Japanese beetles—lay their eggs in the soil under their favorite tree or shrub. To stop the larvae from emerging, lay plastic or a heavy mulch two to four inches thick on the ground around the tree. Begin a couple of inches out from the trunk and extend all the way to the drip line. Lay the mulch down just after the fruit sets or just before the time when you usually start seeing the insects.
As an added precaution against fruit flies, hang yellow sticky traps in trees to catch any that escape the mulch. For green fig beetles, hang cans filled halfway with a solution of 50 percent sugar and 50 percent water on tree limbs. The beetles are attracted to the solution and fall into the water and drown.
Pheromones are substances produced by one organism that influence the behavior or physiology of another organism of the same species. A female gypsy moth produces a pheromone that can attract males that are miles away. Most commercially available pheromones are in the form of sex pheromone traps, used to lure insects looking for a mate or as signals to disrupt mating. These synthetic pheromones are now being produced in the laboratory and are quite species-specific. Pheromone traps attract only adult insects, so can reduce the number of adults that lay eggs, hopefully making a good dent in the population.
There are several different types of pheromone traps. In one, a pheromone lure is placed inside a cardboard container lined with very sticky material. The insect flies in for a rendezvous with a would-be mate, only to find itself stuck to the container walls. These traps come in various shapes and sizes. Anyone familiar with gypsy moth or pantry traps will recognize this sticky trap. Another pheromone trap lures the insect with the same promise but then catches it inside a no-exit container. You can catch Japanese beetles with this kind.
Pheromone traps cannot be made at home; you have to purchase them. Follow the manufacturer’s instructions carefully, and never touch the pheromone capsule or strip with your bare hands. Traps should be replaced whenever dust or debris reduces the trap’s stickiness or in about one month.
Here’s a list of a few of the common pests for which pheromone traps are available. More are being developed all the time. Check with nurseries for the traps available in your area, or refer to the buying guide at the back of this book for companies that make pheromone traps.
| Apple maggots | Flour moths |
| Bagworms | Fruit flies |
| Black cutworms | Gypsy moths |
| Cabbage loopers | Oblique-banded leaf rollers |
| Cherry maggots | Oriental fruit moths |
| Cigarette beetles | Peach tree borers |
| Codling moths | Red-banded leaf rollers |
| Corn earworms | Spotted tentiform leafminers |
| European corn borers | |
Planting trap crops is a great way to catch insects that really love a specific plant. (Of course, this solution will not work if that is the crop you want to grow!) When the insects appear on the trap crop plant, dispose of them as follows:
— Shake the plant to dislodge the insects into a bucket of soapy water. (This works best early in the morning.)
— Hand-pick the insects off the plant. (This works well with caterpillars.)
— Cover the plant with a piece of cloth and pull the entire plant up with the insects still on it; dispose.
— Spray the insects on the trap crop plant with insecticidal soap to kill them.
Plant a few of these trap crops in and around your garden if you have a problem with these insects:
— Aphids: Plant cabbages. Aphids love them. If you want to grow cabbages, try planting nasturtiums nearby. Nasturtiums will also work next to beans and zucchini.
— Cabbage loopers: Plant hyssop, a herb, to attract the butterflies that lay the eggs of the caterpillar near cabbage plants.
— Flea beetles: Plant radishes in spring.
— Harlequin bugs: Plant turnip greens in late summer. Destroy bugs as you see them on the plant.
— Mexican bean beetles: Plant bush beans before pole beans to attract the beetles and reduce their numbers before you plant your pole beans.
— Squash bugs: Plant zucchini before summer squash to catch them and reduce their numbers.
Whatever pest you have, use the plant it loves best in your garden this year to make a trap crop to get rid of it next year. Plant a few of these bait plants along the edges of your garden and some more of them in the center of your garden. The insects may well find the plants along the edges and leave the plants in the center for you!
Row covers can provide a safe and effective barrier against insect pests. Row covers are made of lightweight textiles that will stand up to the elements for many years. They are usually available in many sizes at local nurseries. Here’s how to use row covers effectively against specific insects:
— Asparagus beetles: Place floating row covers over emerging asparagus spears in the spring when adults first appear. Leave covers on throughout the season. Remove at the end of the season when it’s time to remove the old fronds.
— Blister beetles: Protect plants with floating row covers in midsummer if beetle adults become a big problem. Larvae feed on grasshopper eggs and are beneficial.
— Cabbage maggots: Cover seedlings with a floating row cover and bury the edges of the cover in the soil to prevent the flies from laying eggs in the soil. Allow plenty of room in the row cover for the growing plant.
— Carrot rust flies: Cover seedbeds with a floating row cover and bury the edges of the cover in the soil before the seedlings emerge. Allow plenty of room for the carrot plants to grow, and leave row cover in place until harvest.
— Carrot weevils: Cover seedbeds with a floating row cover before the seedlings emerge and the beetles lay eggs on the stems of the carrots. Bury the edges to prevent weevils from crawling underneath.
— Colorado potato beetles: Cover susceptible plants with floating row covers from planting time until midseason. Potato beetles prefer to nibble on young plants.
— Cucumber beetles (spotted) or corn rootworms: Cover seedlings and plants with floating row covers and bury edges so beetles can’t lay eggs in the soil next to plants. Allow plenty of room in row cover for growing plants.
— Cucumber beetles (striped): Cover seedlings with floating row covers and mulch in between plants with straw to discourage beetles. Plants such as squash may need to be hand-pollinated.
— Diamondback moths: Cover plants with floating row covers to prevent moths from laying eggs on the leaves of the plant.
— Flea beetles: Cover plants with floating row covers until adults begin to die off in early July. Row covers also provide shade, which the insects do not like.
— Imported cabbageworms: Cover growing plants with floating row covers to prevent the butterflies from laying eggs on the plant. Butterflies produce three to five generations each year, and covers may need to stay on throughout the season until harvest. To protect cabbage heads from becoming infested, sink a large tomato cage over the heads. Then cover the cage with netting or row cover material to prevent the cabbage butterflies from laying eggs on the heads.
— Japanese beetles: Cover plants with floating row covers to prevent adults from feeding on plants in heavy infestations.
— Leaf miners: Cover seedlings with floating row covers to prevent adult flies from laying eggs on the leaves of the plants.
— Mexican bean beetles: Cover seedlings of bean plants with floating row covers and keep them covered until they are large enough to withstand the damage of the adult beetles feeding on them.
— Onion maggots: Cover onion or leek seedlings with floating row covers and bury the edges in the soil to prevent the adult flies from laying eggs at the bases of the plants.
— Strawberry root weevils: Cover plants with floating row covers and bury edges close to base of the strawberry plants to prevent the adults from feeding on them.
— Tarnished plant bugs: Cover plants with a floating row cover to prevent adults from laying eggs on plant leaves.
Finally, plain old hot water can be a very effective insect and plant control substance.
Pour a couple of gallons of boiling water directly on the mound of an anthill or anywhere you see insects living in the soil. When dealing with fire ants or wasps, be quick: carefully walk up to the mound, pour quickly, and then back away fast. The insects that are not killed will try to escape the nest. It is best to do this in the late evening when temperatures are still warm and the insects are still near the surface but not active outside the nest. Although the hot water usually doesn’t kill all the ants or insects on the first try, you can get rid of them or at least reduce their numbers considerably with repeated dousings.
Are you bothered by slugs? Just a little hot water poured onto a slug will do the trick. Have the water ready when you lift the boards you’ve put down as slug traps.
You can use boiling water on termites you find in deck boards too! Just be sure keep the water from running onto your lawn or prize plants.
Hot water makes an effective quick spray to kill soft-bodied insects like aphids, mites, whiteflies, and mealybugs. The water should be between 120 and 150 degrees. It only takes a second or two of spraying to do the trick.
Connect a hose to your hot water heater or a basement or garage sink for easy spraying. Woody plants tolerate hot water better than some ornamental plants, but always test the hot water on a few leaves to see if it causes any damage before treating a whole plant.