Twospotted Spider Mite
Egg - The minute egg is shiny white and concealed under webbing. It becomes straw-colored or pale green a few hours after it is deposited.
Larva - The six-legged larva, not much larger than the egg, is colorless with distinct carmine eyes.
Nymph - The eight-legged nymph is smaller than but similar to the adult.
Host Plants - Twospotted spider mites have been found on over 180 host plants including over 100 cultivated species. Violets, chickweed, pokeweed, wild mustard, and blackberry are common weeds from which infestations develop on crops nearby.
Damage - Spider mites cause extensive damage to peanut foliage in North Carolina, particularly in the northern Coastal Plain. Yields are often drastically reduced in many fields, especially during periods of hot, dry weather. Initially, leaves appear gray with webbing on the lower surface. As damage progresses, extreme webbing and a burned appearance become very noticeable.
Life History - In North Carolina, twospotted spider mites overwinter as adults on field border vegetation (usually weeds). In mild weather, they continue to feed and lay eggs, though development in the winter is much slower than in the summer. In spring, adults initially infest peanuts near the edges of fields and lay eggs. From these eggs hatch larvae which soon develop into nymphs. After each larval and nymphal stage, there are resting stages. The new adults mate soon after emerging from the last resting stage. In warm weather, the females soon begin laying eggs; each female produces up to 19 eggs per day (up to 100 eggs in all). Each generation requires 5 to 20 days to mature depending upon environmental conditions. Development is most rapid during hot, dry weather.