Banks grass mite

Spider mites, especially Banks grass mite and less frequently twospotted spider mite, Tetranychus urticae Koch, infest sorghum and many species of grasses. Spider mites are more common on sorghum grown in arid areas. Female spider mites, with a body length of 0.40 to 0.45 mm, are larger than males. After feeding, both sexes usually become green, with the exception of the palpi and first two pairs of legs that remain light salmon colored (Color Plate 10). Two dark spots, comprised of food contents, show through the transparent body wall. Eggs (about fifty per female) are laid in webbing on the underside of leaves. Eggs are pearly white, spherical, and one-fourth the size of the female. Eggs hatch in three to four days. Six-legged nymphs are light green; older eight-legged nymphs are darker green. The life cycle under good conditions requires about eleven days.