Rhonda Massingham Hart - Using Beneficial Insects: Storeys Country Wisdom Bulletin A-127

by Rhonda Massingham Hart

These days the healthiest gardens are all abuzz. A garden teeming with insect life is a sure sign of a well-balanced miniature ecosystem. Impossible under the rain of pesticides and insecticides often accepted as conventional pest controls, a varied population of insect life will benefit the garden as no spray ever could.

Of course, all gardeners have problems with insects at one point or another. The number of garden insect pests staggers the imagination. Flies, moths, and butterflies fill the air; cutworms, nematodes, and others choke the soil; and caterpillars, beetles, and a bevy of bugs try to invade everything in between. Whats a gardener to do?

The answer may be a surprising, nothing. Or at least as little as possible. Certainly dont resort to toxic chemicals. For while they may kill off a large number of bugs in one fell swoop, you might be surprised at the actual cost of such control measures. Not so much in dollars and cents, but the cost in contamination of food, soil, groundwater, and insect gene pools.

Chemicals are responsible for a great many modern ills, from increased cancer rates to birth defects. These chemicals often are not merely present on the surface of crops. Some are absorbed by the soil and taken up by the plants roots, which circulate the toxins throughout the plant, infiltrating the entire system of the plant. Chemicals not immediately absorbed by plants eventually make their way to the water table, into wells and other water supplies.

But contamination of food, soil, and water is not the only evil of toxic pesticide use. Wiping out complete bug populations can wreak more havoc on your plot than doing nothing to control them. Pesticides kill indiscriminately: the good die right along with the bad and the ugly.

There are also the inevitable reactions of resistance and resurgence. There are always a few survivors of a pesticide attack. These few quickly reproduce new generations, at least as well equipped to withstand chemical assault as their parents. Mutations occur through successive generations until invincible superbugs evolve.

At the same time, smaller populations of secondary pests find the competition suddenly eliminated. Not only the competition, but all the predators and bug parasites have vanished with them. Uninhibited, these secondary pests can become primary problems.

So what is a gardener to do? If you must resort to pesticides, opt for botanical derivatives, which break down quickly into harmless components, or try the many other organic remedies available, from pheromone traps to soap sprays to bacterial bug bugs. Never overlook the importance of sound cultivation practices, such as soil, weed, and water management. Try a patchwork garden, arranging plants into mixed beds or rows. This slows many a pest who prefers to munch his way down neat rows of his favorite fare. Handpicking bugs and eggs is a valuable practicejust be sure to familiarize yourself with those you find. You wouldnt want to squish a friend!

One of the best methods is to take your cue from Nature herself, and employ good bugs against those bad pests. Encourage predators and parasites, as well as vital pollinators, by including a mix of flowers and herbs among your plantings. You may be in for a treat once beneficial insects come to your rescue. Some will help with pest-control problems, stalking and parasitizing your pests; others will help to improve crop production by pollinating plants; and still others will help to build ever healthier soil by adding organic matter and working the soil to improve fertility and drainage.

The advantages of employing beneficial insects over chemicals are substantial. Beneficial insects create no harmful residues or side effects. Pests cant develop resistance to them, as predators adapt to changes that occur in their prey. Once established, control (a balance between the number of pests and the bugs that prey on them) is virtually permanent. Finally, a small (or even no) initial investment yields big, effective, and safe control.

There are many beneficial insects out there ready, willing, and able to help. They ask only a poison-free environment in which to live, breed, and work, but will thrive given only the basic amenities of food (nectar-producing flowers as well as prey), shelter (wildflowers, herbs, even weeds), and water (often morning dew is all that is necessary, though setting out shallow pans can only be helpful). Lets get to know some of these wonderful helpers and see what we have to offer each other.

Earthworms

To list earthworms among the natural wonders of the earth would only begin to pay them due tribute. A single slimy, squirming worm in the hand may not seem like a living miracle, but the combined forces of trillions perform vital, literally earthshaping tasks every day, everywhere.

Earthworm bodies are virtual humus mills, manufacturing nutrient-rich castings (manure) from nearly anything found in the soil. As they burrow through the earth in their constant search for food, they leave tunnels that improve soil aeration as well as drainage and water retention. All this underworld activity also gives both subsoil and topsoil a thorough mixing.

Actually worms are not insects. They belong to a vast classification of animals called annelids, the ringed or segmented worms. The order Oligochaeta is but a fraction of this diverse group, to which the three thousand or so different kinds of earthworms belong.

The earthworm is a marvel of underground engineering, perfectly designed for his soil-dwelling role. Long, slender, and tapered at either end, the body is made up of many segments. Large night crawlers may have over one hundred fifty segments, while manure worms possess fewer than a hundred. These segments are formed of circular muscles, which make the earthworm incredibly strong for his size. In the course of a day he may shove aside many stones and other bits of debris sixty times his own weight.

The average North American garden-variety worms measure about 4 to 8 inches in length. Most are reddish in color, some with alternating yellowish rings, others are a deep maroon, and some even greenish. All are slimy, the result of a highly efficient kidney system that pumps out fluid wastes through pores located all along the body. This mucus helps them to glide through the soil. Worms have no eyes, though they are sensitive to light, and no ears, though most are unbelievably attuned to vibrations. Though earthworms have a tiny brain, it can be removed without any apparent effect. And earthworms have five hearts!

The worms existence is primarily one of digestion. All of his essential organs are located in the front one-third of his anatomy, but his digestive tube runs the entire length of his body. An earthworm has the ability to regenerate a lost or injured tail, but contrary to childhood beliefs, the tail cannot regrow a new head.

Earthworms make their way through the soil by a combination of muscle contractions and by swallowing much of what lies in their path. Digestive fluids neutralize acids, raising the pH levels of acidic soils. The castings also tend to neutralize alkaline soil, which makes earthworms a valuable asset for balancing soils.

The worms organically rich castings are made up of essential, water-soluble nutrients, easily accessible by plants. Compared to topsoil they contain five times as much nitrogen, seven times as much phosphorus, eleven times as much potash, and three times as much magnesium. Noting that earthworms convert anything available into fertile manure, the Greek philosopher and naturalist Aristotle dubbed these creatures the intestines of the earth.