There may be several generations a year since the entire life cycle can be completed in as little time as 3 weeks. They are usually most abundant on the upper surface of young leaves. The first signs of a mite attack are minute yellow dots at the base of the leaf near the petiole. These chlorotic areas result from the extraction of chlorophyll from the tissues by the mite's piercingsucking mouthparts. Mite-damaged leaves often wilt and drop, leaving numeroug exposed twig terminals.
Defoliation is especially severe when trees under water stress are subject to drying winds.
Red mites are not as prevalent on fruit as on leaves, but damage is similar to both. In Arizona and California where lemons are grown commercially, damage to fruit can be very severe when red mites are not effectively controlled. A survey of the surrounding area revealed 16 infested orchards, all within a 4-mile radius of the initial site. Trees in these orchards were from 6 to 25 years old and included Ruby Red and Star Ruby grapefruit and Joppa, Navel and Valencia oranges. Highest red mite numbers were consistently recorded on young bearing grapefruit trees.