Microscopic Insects in Garden Soil

The Function of Soil Insects and Organisms

• Microscopic insects and other minute soil organisms create an environment for healthy plant growth. As they eat and reproduce, they also create the nutrients that are absorbed by fruits and vegetables. Insects, bacteria, fungi and arthropods transport water throughout the soil, create soil structure and control the population of potentially harmful organism pests. They make up the soil food web, which creates healthy food. Microscopic insects and other organisms in soil depend on its organic matter content to feed them.

Springtails

• Springtails are microscopic insects that contribute to the life of the soil food web. They grow to an average of 1/32 inch in length. Their taillike appendage, known as a furcula, snaps to the ground and causes them to spring in the air and down again. Springtails play an important role in creating healthy soil by feeding on decaying plants, which creates humus. They eat bacteria and fungi on plants, mineralizing some of their contents. The minerals are distributed by the springtails' movement through the soil and are taken up by growing plants. Up to 250 million individual springtails live in 1 acre of soil.

Mites

• Some species of mite are only 1/25 inch in length but play an important part in the biology of healthy soil life. Predatory mites feed on harmful nematodes that sometimes cause plant root disorders, as well as other mites, springtails and the larvae of insects. Microscopic predatory mites help maintain population control of other insects. Larger mites, such as the red-hued velvet mite, emerge in great numbers from the soil after a rainfall. They eat grasshoppers and termites.

Flies

• Flies in their larval stage are maggots. Many species are nearly microscopic when they are in the soil. Maggots feed on mites, thrips and aphids, which are insects that eat plants. Maggots help keep their populations in balance to keep plant damage under control. The activity of creating nutrients for plant life takes place in topsoil, which is the upper 2 to 8 inches of soil. The majority of the soil-dwelling insect population lives in the 3 inches below the soil surface. Larger insect species live closer to the surface.