It is a subterranean aphid, feeding on the roots of beets and reducing both yield and quality. The aphid secretes a white waxy material that covers its body and the root surface. Crop rotation, plowing, and resistant varieties have been occasionally helpful in some parts of the U.S. in reducing this pest. Spider mites are increasing in some drybean and soybean fields. Damaged leaves have a silvery or bronzed appearance from mites extracting the contents out of individual plant cells.
Leaves eventually turn yellow, brown, then drop off the plant.
Look for mites on the undersides of leaves using a hand lens, or by tapping leaves over a piece of paper. Webbing is an indication of a very high mite population. For dry bean and soybean, treat when 25 percent of the plants have mites, and yellowing is seen. Use a product like dimethoate. Thrips often can start out on wheat, then move to other crops as the wheat dries down.