Whether your garden pest is a weed, an insect, an animal, a microbe, or other organism, a pest is a pest! Correct identification of it makes controlling it easier and often more effective. Mistaken identity will cost you time and money, and unnecessary risks to people and the environment.
Integrated Pest Management
• Biological control is the use of natural enemies—predators, parasites, pathogens, and competitors.
• Cultural controls use practices that reduce pest establishment, reproduction, dispersal, and survival.
• Mechanical and physical controls kill a pest directly or make the environment unsuitable for it.
• Chemical control is the use of pesticides, where the pesticides are selected and applied in a way that minimizes their possible harm to people and the environment.
Insecticides are substances applied to control, prevent, or repel insects. Insecticides can be a part of IPM programs, however, some products can worsen the problem or harm people or wildlife. Products labeled “less toxic pesticides” cause few injuries to people and organisms other than the target pest. Even organic pesticides can be dangerous and can kill Honeybees and birds if overused.
• Soaps (potassium salts of fatty acids). Insecticidal soaps control aphids, whiteflies, and mites and require complete coverage of pests and sometimes a repeat application.
• Insecticidal oils. Oils control aphids, lacebugs, mealybugs, psyllids, scale insects, spider mites, thrips, and whiteflies. Good coverage of plants is required. Don’t apply to water-stressed plants or when temperatures are above 90°F. Petroleum-based oil products include superior, supreme, narrow range, and horticultural oils. Plant-based oil products include jojoba, neem, and canola oils.
• Microbial insecticides. Microbials are derived from microorganisms that cause disease only in specific insects.
• Bacillus thuringiensis subspecies kurstaki (Bt) controls leaf-feeding caterpillars.
• Bacillus thuringiensis subspecies israelensis (Bti), sold as mosquito dunks, controls mosquitoes.
• Spinosad is a microbial-based insecticide that controls caterpillars, leafminers, and thrips, but it also can harm some beneficial insects.
• Insect-feeding nematodes. Nematodes species are microscopic worms that attack many underground insects. Because they are living organisms rather than a pesticide, they are very perishable, so order through the mail to assure freshness.
• Botanical insecticides. Derived directly from plant materials, botanicals vary greatly in their chemical composition and toxicity but usually break down in the environment rapidly.
• Pyrethrins (pyrethrum) are used against a range of insects but toxic to fish and aquatic organisms.
• Azadirachtin, from the neem tree, has limited effectiveness against pests but low toxicity to nontargets. Don’t confuse with neem oil.
• Garlic, hot pepper, peppermint oil, and clove oil are sold as insect repellents that protect plants.
• Non-toxic and homemade remedies. Homemade remedies are inexpensive and, best of all, you know what’s in them. Many homemade sprays have been used with good results to control insects. They usually involve noxious (but non-toxic) ingredients such as garlic, cayenne, stinging nettles or horsetail which are diluted in water and blended to be sprayed on the plants.
• Pyrethroids such as permethrin, cyfluthrin, cypermethrin, and bifenthrin move into waterways and kill aquatic organisms.
• Organophosphates such as malathion, disulfoton, and acephate are toxic to natural enemies.
• Carbaryl harms bees, natural enemies, and earthworms.
• Imidacloprid is a systemic insecticide that can be very toxic to bees and parasitic wasps, especially when applied to flowering plants.
• Metaldehyde, a common snail bait, is toxic to dogs and wildlife. Use iron phosphate baits instead.
• Pull out weak plants. They may already be infected, and if not, they will attract problems.
• Build a healthy soil. Composting methods, adding organic matter, mulching and top-dressing your soil with compost or natural fertilizer is the best way to develop strong, vigorous plants.
• Seaweed mulch or spray contains trace elements such as iron, zinc, barium, calcium, sulfur and magnesium, which promote healthy growth in plants. Seaweed fertilizer in mulch or spray form will enhance growth and give plants the strength to fight off disease. Seaweed mulch also repels slugs.
• Minimize insect habitat. Clear the garden of debris and weeds which are breeding places for insects.
• Interplant and rotate crops. Insect pests are often plant specific. When plantings are mixed, pests are less likely to spread throughout a crop. Rotating crops each year is a common practice to avoid re-infestation of pests which have over-wintered in the garden.
• Keep foliage dry. Water early so the foliage will be dry for most of the day. Wet foliage encourages insect and fungal damage to your plants.
• Disinfect. If you’ve been working with infested plants, clean your tools before moving onto other area in the garden. This will reduce the number of invading insects.
• Hand-picking. For small infestations, hand-picking is an effective and easy way to remove insects. Fill a jar with water and a few teaspoons of liquid soap and take it into your garden. When you see a caterpillar or insect, pick it from the plant and drop it into the jar. Squish small insects like aphids against a leaf with your fingers.
• Companion planting. Some plants have natural properties that repel insects. Plant these companions next to plants that are susceptible to insect attack. For example, plant onions near cole plants to repel cabbage loopers, and marigolds next to tomatoes and peppers to repel root-knot nematodes in the soil.
• Yellow flypaper. Old-fashioned fly-paper is very effective in the garden for aphids and whiteflies. In fact, any board or heavy paper painted yellow and coated with a sticky substance will do the job.
• Pheremones. These biological mating scents attract insects to a trap which is coated with a sticky substance. Pheremone traps are effective, but remember they are “attracting” the insects, so be sure to position them on the outskirts of the garden perimeter or you’ll attract them straight to your garden!
• Floating row covers. These consist of lightweight opaque fabric that’s draped over the garden bed. Sunlight and water can penetrate, keeping insects and birds out. The material is so light that the growing plants lift it up as they grow. Anchor down the edges with rocks or boards or the wind will blow it off. Row-cover fabric comes in rolls so you can make a continuous cover no matter how long the garden bed is. Row covers are very effective for protecting seedlings. When placed over vegetables such as beets, broccoli, cabbage, spinach and swiss chard, it makes an effective barrier against flying insects looking for these plants on which to lay their eggs.
• Cloche. The cloche acts like a miniature greenhouse for seedbeds and young plants, and acts as a barrier against pests. Unlike the floating row cover, the cloche has to be opened on hot days and for watering. It helps seedlings and young plants get well established, developing their natural resistance against pests and disease.
• Barrier paper. Milk cartons are a simple, effective way to protect plants from cabbage moths larvae. They kill young sprouts of the Brassica family (broccoli, cabbage, brussel sprouts, kale or cauliflower) by nibbling at the base. Cut the cardboard into 2″ squares and slit one side into the center; make another small slit crossways. Open the slit and slide the square so the seedling stem is in the center. This prevents the cabbage moth from laying eggs at the base of the sprouts. As the plant grows, it will push the slit open wider.
• Spray protection. Use diatomaceous earth as dust or in a water-spray for effective control of hundreds of species of insects. It works by scratching their exoskeletons and dehydrating them. Insecticidal soaps are made up of fatty acids that break down the cell structure of the insects’ exoskeletons and cause dehydration. Oil or wax sprays coat the insects’ bodies and smother them. Some oils and waxes contain other ingredients such as capsaicin (hot pepper oil), which is toxic to insects. These remedies are broad-spectrum and are toxic to beneficial as well as harmful insects.
Garden “mini-insectary.” Set aside a small garden plot of flowering plants designed to attract and harbor beneficial insects. These good insects prey on many common garden insect pests, and offer the gardener a safer, natural alternative to pesticides.
• Brachonids, chalcids and Ichneumon wasps: These small beneficial insects attack leaf-eating caterpillars. You can attract them to your garden by planting carrots, celery, parsley, caraway and Queen Anne’s lace. Leave some to flower because it’s the flower that attracts the insects.
• Ladybugs: These common insects consume aphids, mites, scales, and whiteflies. Attract them to your garden by planting flowers of the Compositae family such as tansy or yarrow. Ladybugs can be purchased at your nursery or from catalogs and released directly into the garden.
• Lacewings: Lacewings love aphids and a variety of other insects. They’re also attracted to “composite” flowers, such as asters, black-eyed Susan, goldenrod, and yarrow. Lacewings can also be purchased and released directly into your garden.
• Hover-flies: These also enjoy aphids. The larvae of hover-flies eat other insect pests as well. Like the lacewings, they are attracted to composite flowers.
• Praying mantis: These large insects have an appetite for most garden pests. Praying mantis eggs are set out in the garden where they hatch and quickly grow to adult size. The eggs are available at nurseries and through catalogs.
• Nematodes: Nematodes are effective against cutworms that eat the sprouts before they can grow into seedlings. Nematodes are also effective against beetles and root weevil larvae. Nematode eggs are microscopic and come in a small sponge containing over a million eggs. They are mixed with water and applied to the soil, where they hatch and get to work. If they get on any foliage, wash them off to the ground. They are available in some nurseries and through mail-order catalogs.