Living on the Earth, July 9, 2000: Not All Insects are Bad Imagine being able to leave the weeds, while you grow flowers, herbs, vegetables and fight insect pests at the same time. That's the implication of research on the use of beneficial predatory insects to control plant-eating ones. Of all the great variety of insects in the environment, believe it or not, only a few pose a threat in the garden. The majority of insects are either neutral or actually beneficial. Some of these are important for pollination. Other good "bugs" such as hoverflies, minute pirate bugs, ladybugs, bigeyed bugs, lacewings and spiders dine voraciously on pests like aphids, thrips, mealybugs, flea beetles, gypsy moths, corn borers and coddling moths. Beneficial insects, like other living things, need habitats as well as sources of food and water throughout the course of their lives. By providing a diversity of plants to supply their pollen, nectar, food and shelter needs over the growing season we secure their expert pest-eating services. Research shows that these useful predatory insects are especially attracted by common flowering plants, including some weeds, and even by garden herbs. Small-flowered plants are particularly important. Cosmos, marigolds, sweet alyssum, yarrow and sunflowers encourage beneficial predatory insects. Herbs such as coriander, parsley, dill, fennel, and mustards as well as such so-called weeds as dandelions, clovers, Queen Anne's Lace and goldenrods also attract and nourish beneficial insects. Even buckwheat and winter rye cover crops can help eliminate pests while they control weeds and build soil. Leave these plants in the garden for a longer time without mowing or plowing them under so that the good insects can complete their life cycles. A study of these insects clarifies the value of growing and encouraging a diversity of plants. Of course, the current culture leans in the opposite direction with lawn and farm monocultures carefully maintained by mowing, plowing and the use of herbicides. Insecticides often kill off more good bugs than bad ones, leaving pesticide-resistant insects with no natural enemies to control them. Some pests are necessary to attract and feed the predators. Of course it always pays to take the basic steps to minimize pest pressure: create and maintain a healthy soil, plant appropriate varieties at the right time, rotate crops and keep your eyes open for troublesome insects like the Colorado potato and Japanese beetles. However, more and more organic gardeners and farmers find that by maintaining a diversity of plants in the vicinity of their crops, they have much less trouble with insect pests. This is Bill Duesing, Living on the Earth (C)2000, Bill Duesing, Solar Farm Education, Box 135, Stevenson, CT 06491 For specific information about plant, insect and pest relationships see the ATTRA publication: Farmscaping to Enhance Biological Control, available on line at http://www.attra.org/attra-pub/farmscape.html or call 1-800-346-9140. Bill and Suzanne Duesing operate the Old Solar Farm (raising NOFA/CT certified organic vegetables) and Solar Farm Education (working on urban agriculture projects in southern Connecticut and producing "Living on the Earth" radio programs). Their collection of essays Living on the Earth: Eclectic Essays for a Sustainable and Joyful Future is available from Bill Duesing, Box 135, Stevenson, CT 06491 for $10 postpaid or from any bookseller. Now in its tenth year, "Living on the Earth" airs at 6:53 Friday mornings on WSHU, 91.1 FM Public Radio, serving Connecticut and Long Island. Essays from 1995 to the present, and an audio version of this week's essay are available at www.wshu.org/duesing. Distribution of these essays is encouraged. Reprinting rights available by request. If you are interested in receiving these weekly essays do nothing more. If you would like not to receive these mailings, please let me know.
