Trees, Shrubs, and Vines: Spider Mites

Problem
Leaves are stippled yellow, white, or bronze, and are dirty. Sometimes there is a silken webbing on the leaves or stems. New growth may be distorted, and the plant may be weak and stunted. To determine if the plant is infested with spider mites, hold a sheet of white paper underneath an affected leaf or branch and tap it sharply. Green, red, or yellow specks the size of pepper grains will drop to the paper and begin to crawl around.

Analysis
Spider mites, related to spiders, are major pests of many plants. They cause damage by sucking sap from the leaves and buds. As a result of feeding, the green leaf pigment disappears, producing the stippled appearance. While they feed, many mites produce a fine webbing over the foliage that collects dust and dirt. Some mites are active throughout the growing season, and are especially favored by dry weather with temperatures of 70°F and above. Other mites, especially those infesting conifers, are most prolific in cooler weather. They are most active in the spring and sometimes fall, and during warm periods in winter in mild climates. At the onset of hot weather, these mites have usually caused their maximum damage. For more information about spider mites, see Mites.

Solution
Spray with a miticide containing hexakis or with a horticultural oil when damage is first noticed. Repeat the spray 2 more times at intervals of 7 to 10 days. Make sure your plant is listed on the product label.