All spider mites are pests of cultivated plants, particularly under dry and warm conditions. They are oval in shape, greenish, yellowish, or reddish, and are so small that they are barely visible without the aid of a magnifying glass. Spider mites are found mainly on the undersurfaces of leaves, but in heavy infestations a small percentage may be seen on other parts of the plant. When the mites are very numerous, a silky webbing may be found covering infested areas and extending from leaf to leaf to cover the entire plant. Mites can be seen crawling over this webbing.
Spider mites suck out plant juices.
The removal of chlorophyll results at first in whitish or yellowish speckled areas on the upper surfaces of leaves, and eventually in a more uniformly bronzed or yellowed discoloration, possible defoliation, and stunting or even death of the plant. For plants that are sufficiently sturdy, a forceful spray of water may be enough to break up the webbing and dislodge the mites. Tender plants may be treated with the dip or spray without the preliminary water spray. Several applications may be required, at weekly intervals. False Spider Mites Brevipalpus obovatus Donnedieu, the privet mite, is the principal species involved as a pest of house plants.