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NOT AN INSECT BUT STILL A PESKY NUISANCE

written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA
published- MAY 23, 2014

NOT AN INSECT BUT STILL A PESKY NUISANCE

Some years certain insect populations will generate concern with a sudden spike in their numbers. This spring, one such creature causing some worry is the clover mite. Technically this large mite is not an insect. It is an arachnid and is more closely related to spiders, ticks, and scorpions. As a group, arachnids have eight legs, no wings, and two body sections. Adult insects have six legs, three body sections, and most also have wings.

Let’s get back to our clover mite problem. These mites are very visible, being just a little smaller than the head of a pin. Their body pigmentation is bright brick red turning to a reddish brown as they grow older. They have eight legs, but at first glance the front legs look like antennae because they are longer than their other six legs.

Clover mites feed by sucking out plant juices from the leaves of mostly grass and clover, but they may also feed on low growing ornamental plants. They do not bite humans or other animals. The plant damage caused by their feeding is characterized by stippling or meandering silver streaks in leaves. It is usually not severe enough to harm a plant or even be noticed by gardeners. However, clover mites can become a nuisance when they accidentally enter homes. Indoors they are annoying because they cause a reddish stain when crushed.

To understand their periodic “sudden” appearance let’s talk a little about their life cycle. Clover mites spend the cold winter and hot summer months mostly in the egg stage. They hatch from eggs in the spring and fall when temperatures are between 70 and 85 degrees. After hatching, they feed on plants and proceed through three stages of growth before becoming egg-laying adults. There are multiple generations each year.

In the fall, clover mites try to find a protected spot to spend the winter. This cosy spot may be somewhere outdoors or within the outside walls of the home. When looking for an overwintering spot, some mites may accidentally enter the house. In the springtime when sun warms up outside walls of the home, especially south and eastern facing sides, the overwintering mites within the walls can become active and again accidentally come inside. Clover mite invasions are usually most severe when grass and weeds are allowed to grow up close to a building, especially where the grass is lush and heavily fertilized.

Indoors, clover mite control is best accomplished using a vacuum to suck the critters up without squashing them or wiping them up carefully with soapy water and a sponge. On the outside of a building or structure, simply squirt them off with soapy water. Any of the insecticidal soaps should work well, but make sure whatever you use does not stain the finish.

To prevent future outbreaks, consider not allowing grass to grow up next to the foundation by creating a two feet or more deep landscape bed around the home. To help with weed control, mulch this “grass free zone” with a three to four inch layer of bark or pea gravel. You may also want to make the bed deeper and plant it with ornamental shrubs and flowers.

It is also a good idea to “tighten” up your home by caulking outside cracks and crevices around windows, doors, and the foundation. This is helpful in preventing clover mites, spiders, and other pesky insects… and non-insects from becoming a nuisance indoors.

Published: 5/23/2014 11:51 AM

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