Spider mites are common plant pests that are found on the underside of leaves. Their feeding can cause leaves to discolor, causing a speckled appearance. With severe infestations, the plant leaves discolor to a silver or bronze color which may result in the leaves dropping from the plant.
Spider mites are arachnids, closely related to spiders and ticks. Similar to spiders, spider mites can produce silk and often cover leaves with web-bing, especially when there are large populations. The webbing helps to protect the mites and their eggs from natural enemies and harsh environ-mental conditions.
Spider mites lay their eggs along the leaf vein during the growing season. Eggs are round and large in size when compared to the adult mite. Some species of spider mites peak during warmer months of the year while others become more active in the cooler months of the year. The mites are able to develop more quickly when temperatures are warmer, so populations can grow very quickly. Spider mites thrive in dry condi-tions. Their natural enemies require more humid conditions, so dry conditions allow spider mite populations to grow with little predation or parasitism that would keep the population at an acceptable level.There are many predatory arthropods that feed on spider mites. Some of these include predatory mites, spider mite destroyers (a type of lady-bug), minute pirate bugs, big-eyed bugs and predatory thrips. Proper watering of plants may also help to reduce spider mite outbreaks as watering plants can help reduce stress brought on by drought. Using strong jets of water to hose plants can also help to dislodge spider mites on infested plants. Miticides or aca-ricides can be used to manage spider mite outbreaks. Look for active ingredients such as horticultural oils, insecticidal soaps, abamectin, bifenthrin, dimethoate or acephate.
