Heavily infested plants may be discolored, stunted or even killed. Web producing spider mites may coat the foliage with the fine silk which collects dust and looks dirty. Spider mite species seem to be warm weather or cool weather active pests. The twospotted, and red spider mite, do best in dry, hot summer weather. The spruce and southern red spider mites do best in cool spring and fall weather.
All spider mites go through the same stages of development.
Adult females usually lay eggs on their host plants. The eggs hatch in days to weeks into the first stage, called a larva. Larvae are round bodied and have only three pairs of legs. The larvae feed for a few days, seek a sheltered spot to rest and then molt into the first nymphal stage. The first nymph now has four pairs of legs.