Pest Control Techniques for the Home Garden

As midsummer vegetables ripen, garden pests abound. Identifying pests is the key to selecting appropriate controls, whether gardeners choose pesticides or alternative techniques.

Generally, pests include any living organisms that interfere with crop growth, including insects, diseases, weeds, rodents, birds and even dogs. A good fence will help keep dogs out. For birds, try netting to protect crops. Buried hail screen or hardware cloth can protect gardens from most rodents. Pesticides are occasionally used to control insects, diseases and weeds, but there are also many effective non-chemical techniques. Insecticides generally kill insects that chew treated plant parts or that suck them up through plant sap. Some insecticides are absorbed through insect skin. Insects may also be controlled with proper sanitation, such as cleaning up old leaves where insects over winter. Biological controls include natural insect predators like lacewings, ladybugs, and praying mantes. Be careful with insecticides, because they can indiscriminately kill beneficial insects along with pests.

Sprays containing the bacteria Bacillus thuringiensis (BT) are another natural way to control pests like the cabbage looper. Because BT sprays are specific to these and other types of caterpillars, they won't harm other insects, animals or humans. Most plant diseases are caused by fungi, bacteria, viruses and microscopic parasitic worms known as nematodes. Generally, fungi are the largest group of plant pathogens. Many fungicides are applied to plants before disease occurs to prevent infection. Good sanitation and use of improved plant varieties with resistance or tolerance to specific diseases are the most environmentally friendly methods for controlling disease. The letters "VFN" following a tomato variety name refer to resistance or tolerance to Verticilluim wilt, Fusarium wilt and nematodes. Irrigating squash or melon plants in the morning rather than the afternoon will allow plants to dry out and reduce the incidence of powdery mildew. Viruses are hard to control and are often spread by aphids, thrip, and leafhoppers. Curly virus, which affects tomatoes and peppers, is spread by beet leafhoppers. When infected, tomato plants become stunted with curled leaves and purple veins. Chile plants will look stunted and yellow. Simply pull the infected plants up and discard them.

Commercial growers control most weeds with herbicides and proper cultivation methods. For home gardeners, the hoe is the most effective technique. It's environmentally friendly and provides good exercise. Mulches help control annual weeds. Both organic and plastic mulches will shade the ground, preventing weed germination. Plastic mulches also help control perennial weeds like bindweed. Both types of mulch will slow down evaporation from the soil, conserving water. As organic mulches decompose, they will return nutrients to the soil and to plants.

For more information, please visit New Mexico State University's Cooperative Extension Service (CES) Publications website.