Lower branches may lose all of their needles, except new growth on spruce.When the mite population is very high, webbing may be noticed on the needles.The damage is usually first observed on the older needles at the base (or one side) of the tree (or shrub), eventually moving up the tree (or shrub).Damage appears as tiny yellow stipples on needles.Some spider mite species may produce webbing that covers leaves and stems when populations are high.The two-spotted spider mite feeds mainly on the undersides of the leaves.During feeding, some mite species may inject toxins that cause varying degrees of leaf discoloration and distortion. Heavy mite feeding causes yellowing, browning of leaves, and eventual leaf death.The result of this feeding appears as minute white dots or flecks called “stipples”.As spider mites feed they suck out the green chlorophyll in leaves.This is the most common spider mite found in homes and greenhouses. The two-spotted spider mite, which is the most common spider mite species, overwinters as orange adult females that hide in bark crevices. Most species of spider mites overwinter as white, brown, or red eggs.Unlike other mites, it prefers cooler temperatures in early spring and late fall, and this is the best time to control them. The spruce spider mite attacks many conifers, especially dwarf Alberta spruce.Spider mite activity can occur any time after plants leaf out in the spring until early fall.This is why spider mite populations often build up so rapidly. During hot summer weather, female two-spotted spider mites live about 30 days and produce about 100 eggs. There may be up to 20 generations in a year depending on the weather.In hot weather, the generation time may be as short as one week.Spider mites develop through 5 stages from egg to adult.