Maple trees are an attractive addition to any landscape. There are a wide variety of maple trees to choose from, such as the Japanese lace leaf maple, the red maple and the silver maple. Maple trees are susceptible to infestations of pests such as spider mites, which affect the appearance and overall health of the tree.
Washing maple trees infested with mites with a forceful stream of water often knocks the mites from the tree. According to Colorado State University Extension, periodically washing trees with hard streams of water physically removes mites from the tree and is an effective means of control of mild mite infestations. Hosing maple trees with mites with water also disturbs the webbing produced by certain types of mites such as spider mites. Mites must take time to produce more webbing, which delays egg laying. Providing adequate water for maple trees during mite outbreaks is important, because trees under stress from drought are more susceptible to mite infestations.
Natural predators, such as predatory thrips, lady beetles and minute pirate bugs, feed on mites and are often an effective way to control mite infestations in trees. Using insecticides often contributes to the development of mite infestations in outdoor trees, because the chemicals destroy natural predators of mites. Colorado State University Extension states that using carbaryl eliminates most natural enemies of spider mites, making outbreaks more severe. Other insecticides such as malathion and imidacloprid also kill insects that eat mites. Purchasing predatory mites often helps control mite infestations in plants. Consult with a supplier of predatory mites to determine if this is an effective means of outdoor mite control in your maple tree.
Chemicals especially designed for controlling and eliminating spider mites may help reduce mite infestations in maple trees. Miticides may not affect egg development, so it is usually necessary to repeat the application in 10 to 14 days after the original treatment. Horticultural soaps and oils are often used in the treatment of mites, as well. Maple trees such as the red maple and Japanese maple are sensitive to the effects of horticultural oils, so use these with caution, states Colorado State University. According to Ohio State University Extension, applying dormant oils on maple trees is discouraged because it can damage the tree's twigs and leaves. However, dormant oils may kill maple bladder gall and spindle gall mites if the trunk of the tree is drenched in the oil.