The first sign of infestation by twospotted spider mite is usually a chlorotic, stippled appearance on the leaves, although this may not be as apparent on thick-leaved plants. As the mites feed on the underside of leaves, they remove leaf cell contents, including the chlorophyll that gives the leaves their green color. Without the chlorophyll, those empty cells appear whitish or bronze. Heavily infested leaves turn completely pale, dry up, and fall off.
Large populations can severely defoliate or kill plants.
The mites also produce fine silken webs over which to crawl. The undersurfaces of leaves are often completely covered with webbing. When the mites are numerous, their webbing can cover foliage and flowers, detracting from the appearance of the plant. Typically mites are discovered only when damage on the plant becomes noticeable. Twospotted spider mites range in color from light yellow or green to dark green or brown.