Get Rid of Garden Pests

Get a handle on garden pests with these helpful tips.

| Summer 2012

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.

Quite often when you see damage on the leaves of a vegetable plant, the plant is not necessarily in danger of dying, only being nibbled on by an occasional insect. Sometimes your plant will be nibbled away overnight by some hungry snail or slug, cut off at the base by a cutworm, or dug out of the ground by a squirrel. This can be frustrating when it happens, but remember that we share this earth with these creatures and your garden is also home to them. Most of the time, simple, time-tested control methods are the best solutions.

Integrated Pest Management

Integrated pest management (IPM) is the monitoring and identification of pests, and the subsequent control of those pests. After monitoring and gathering information about the pest, its life cycle, and environmental factors, you can decide whether the pest can be tolerated or whether it needs to be controlled.

IPM combines the most effective, long-term way to manage pests by using a combination of methods that work better together than separately. Approaches for managing pests are often grouped in the following categories:

• 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.

The less-toxic insecticides listed below should be a first choice when choosing a pesticide. Pick any pest and you can usually find a natural control for it. Always check the product labels to be sure they are registered for that plant or pest situation.


Less-toxic insecticides include:

• 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.

Avoid these more-toxic pesticides:

• 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.

Cultural Controls

The easiest and first way to prevent insect damage in your garden is to discourage the pests from coming in. A healthy garden is your best defense. Here’s how to ensure that:

• 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.

mother earth news fair 2018 schedule


Next: April 28-29, 2018
Asheville, NC

Sit in on dozens of practical workshops from the leading authorities on natural health, organic gardening, real food and more!