Spider Mites (Tetranychus urticae, Tetranychus spp.)



Spider mites are small pests, with adults about the size of a small pinhead, variable in color (green or yellow) with dark pigmented spots. Adult spider mites have eight legs and are oblong to spherical in shape. The eggs of spider mites are very small, whitish, and spherical in shape. You will need a hand lens to see them.

Spider mites are usually found on the undersides of leaves, with colonies beginning on the lower (older) leaves and moving upward on the plant.


Spider mite feeding first appears as stippling (smallyellow areas) on leaves. Severe damage desiccates leaves, and they may fall from the plants. Heavily infested plants may be stunted and have a yellowish appearance. Tonnage reduction of almost 0.2 tons of hay/acre has been documented from severe spider mite infestations. Reductions are thought to be greatest when hay is growing slower and/or when infestations occur early in the cutting cycle.