Lady beetles and lacewings devour aphids and mites
Did you know that less than one percent of all insects are harmful to plants?
Many are actually beneficial, feeding on harmful insects and assisting in the cross-pollination of certain plants. Yet, too often we control pests by indiscriminate spraying - killing beneficial and harmful insects alike. There are many effective alternatives to spraying. Here are some environmentally friendly ways to control insect pests in the home garden and landscape.
Don't attract plant feeding insects. They prefer soft, succulent, leafy growth, the kind that comes from excessive fertilizer and water. Moderate amounts of both maintain the quality of your garden and landscape. Too much will invite insects such as aphids and white fly.
Check your plants frequently. Walk around your yard and look for spotted or yellowing leaves. Use a magnifying glass to look closely at leaves, particularly the undersides. You can also use a white sheet of paper to shake leaves against. If insects such as aphids or mites are present, you'll see them crawling against the white background. Frequent scouting allows you to identify and treat problems before they get out of hand.
Know when control is needed. Insect pests come and go. Most don't do enough damage to warrant control. Aphids are a good example. They are small soft-bodied, sucking insects, which come in a variety of colors from green to brown and shades between. They are usually found on the new growth of plants and cause a yellowing and curling of the leaves. Damage to plants is slight and temporary. The aphids are gone in a week or so, leaving plants to resume normal growth without the need for spraying.
Use mechanical control methods. Many insect problems can be reduced or eliminated by hand picking or pruning off affected leaves or plant parts. The heel of your shoe can be an effective form of pest control.
Protect beneficial insects. If you have harmful insects, chances are, you also have a host of beneficial insects and organisms waging war against them. Beneficials like lady beetles, parasitic wasps, lacewings and spiders eat a multitude of pests like aphids, mites and white flies. Let them do their work. Broad spectrum pesticides such as Dursban, Sevin, diazinon and malathion kill many kinds of insects, good and bad. So-called organic pesticides such as rotenone and pyrethrum are as lethal to beneficials as some inorganic pesticides. Soaps and BT (Bacillus thuringiensis) are less harmful to beneficials and do a good job of controlling a wide variety of pest insects. Learn to recognize beneficials such as lady beetle larvae and lacewings by referring to garden book illustrations. When you see them, let them do the control work for you.
Don't spray leafcutter bees. These are beneficial pollinating insects. Right now they are cutting out neat half-circles from a variety of plants. Their favorites are roses, bougainvillea, ash, redbud and other plants with thin, smooth leaves. Females do the cutting and use the leaf sections to fill small thimble-sized holes for the development of their larvae. Although cut leaves cause alarm and sometimes plants can be completely stripped, no lasting damage is done. Plants will put out new leaves to replace those cut off by the bees.
Buy knowledge, not pesticides. If a professional company maintains your landscape, insist they apply pesticide sprays only as needed and only to affected plants. Request spot treatments of problems, and don't allow blanket sprays. Remember that with pesticides, more is not better. Effective scouting for pest problems is a valuable service provided by qualified professionals. Pay for their expertise and use their chemicals only when necessary.