Finding holes in the lettuce and cucumbers is discouraging for vegetable gardeners, but resorting to chemicals usually backfires. Pesticides are toxic and kill beneficial insects, along with pests. Additionally, they may not eliminate the problem. An integrated pest management system that incorporates several natural strategies for pest control is a better bet.
Good soil amended with plenty of organic material, such as compost and manure, builds healthy plants that rebound from damage done by insect invasions. Careful plant selection also helps minimize the damage done by pests. Some plants are so prone to bug problems, they might not be worth the trouble. Others may become infested at certain times during the growing season. Planting them a bit earlier or later may eliminate the problem.
Insect repellents for the vegetable garden include mechanical, cultural and biological controls, according to the Alabama A & M and Auburn universities. Mechanical controls rely on hand-picking insects and installing barrier devices, such as row covers, collars and traps. Cultural controls, such as companion planting and rotating crops, thwart pests through the use of carefully planning where and when to plant crops. Biological defenses include the use of biocides, such as Bacillus thuringiensis, or Bt, and encouraging beneficial predatory insects and animals, such as frogs, snakes, birds, ladybugs and lacewings to the garden by providing food and shelter.
An integrated pest management system keeps pests in check using natural means that don't harm the soil, water or living things. Gardens may sustain some damage from insects, but usually not enough to warrant the use of pesticides.
Properly identifying insects is an important part of managing pests in the vegetable garden for several reasons. Products such as Bt are made to kill specific insects and are ineffective on any other kind, advises Barbara Damrosch, landscape designer and author of "The Garden Primer." Additionally, without proper identification, gardeners may unknowingly kill beneficial insects.
Pesticides have been linked to increased rates of cancer, according to the National Cancer Institute, and home gardeners are among the groups most at risk of overexposure. Even organic pesticides, such as rotenone and pyrethrum, can harm groundwater, wildlife and humans. Additionally, pesticides kill beneficial insects, including bees, lacewings and ladybugs. Bees are needed in the garden to effectively pollinate many crops. Without lacewings and ladybugs, insect populations can proliferate, creating a larger problem.