Archive for Thursday, May 12, 2005

Cool-season lawns entice grain mites

May 12, 2005


As mild spring temperatures continue to linger, many gardeners are able to relax on the back patio after a hard day's work.

However, after sitting just a few minutes, gardeners may start to realize thousands of tiny bugs are crawling over everything. Winter grain mites are commonly found in the wheat fields of Kansas. However, they can also be found in Kentucky bluegrass, perennial ryegrass and tall fescue lawns.

As the name implies, winter grain mites are normally found in wheat fields during the winter months. However, cool-season lawns are just as suitable of habitat. Young mites are reddish-orange and hard to find. Adults are black bodied with reddish-orange legs and are about the size of period on a piece of paper. Winter grain mites are a unique turf pest because they feed during the winter to early spring and spend summer in the egg stage. Damage often appears from January through mid-March and is evidenced by a silvery, scorched appearance to the turf. Mites feed on cloudy days or at night. On sunny days the mites can be found on the crown of grass plants or in the thatch layer. They feed by rasping the leaf surface and sucking up the plant sap released. The silvery effect is caused by the loss of chlorophyll and plant sap. Unfortunately, they are not harmed by short periods of sleet, ice or frozen ground. In fact, they can actively feed under snow.

Normally, these pests die out by mid- to late April. However, with the cool spring temperatures this year, they are still alive and climbing on patios and furnishings left out in the yard. Some are even being found indoors as they climb through open windows and around doors. They do not cause harm or bite. They are considered a nuisance because of their numbers and green spots they leave when smashed. Although they will naturally die as the weather continues to warm, those present can be killed with aerosol sprays containing pyrethrum or allethrin. There is no residual effect so several applications will have to be made. Household insecticides containing resmethrin, premium grade malathion or lamda-cyhaluthrin have a longer residual effect. When sprayed around doors, windows and other areas where mites enter, they may reduce the number of mites in the home.

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