They are green-yellow with two large, irregularly shaped black spots on each side of the body. Twospotted spider mites can complete their life cycle in 10 to 20 days, depending on weather conditions. Twospotted spider mite injury to soybean plants at the field edge. Twospotted spider mites clumped at the tip of a soybean leaflet. Twospotted spider mites overwinter as females in noncrop areas such as field margins.
Spider mites disperse by crawling and by airborne movement.
Their crawling from the weeds in field margins to soybean plants usually results in initial infestations along field edges. Initial symptoms of injury include yellow stippling of the leaves and stunting of the plants. As injury becomes more severe, leaves turn completely yellow and may turn brown, die, and drop from the plants. If densities of the mites continue to increase, the mites group up at the tips of leaflets and spin out strands of webbing that catch in the wind, which carries the mites to other areas of the field. Management of twospotted spider mites in soybeans depends greatly on vigilance.