CLOVER MITES

CLOVER MITES IN HOME LAWNS

S. Bambara, Extension Entomologist

CLOVER MITE, Bryobia praetiosa Koch, Tetranychidae:ACARINA

General Information

Clover mites are more often an annoyance in northern states, but have been noted as a pest in different parts of North Carolina during certain years. If populations build to large numbers, they may invade homes, overrun floors and furniture and create great worry among homeowners. Homeowners often first notice them as tiny moving red dots on sidewalks or foundations. Severe infestations may cause tiny stippling in turf leaves that could slightly reduce the intensity of green color, however, damage is not severe enough to justify treatment on turf under normal circumstances. They do not bite people, transmit diseases or feed on furniture or pantry items. There is an old, suspect, isolated report of skin irritation from Argentina from children scratching at the mites. When crushed, however, they may leave a tiny red stain. Other common names for this mite are Ivy red spider mite and Bryobia mite.

Adult clover mite. Photo credit-Missouri Cooperative Extension

Identification

Clover mite adults are are slightly larger than the familiar twospotted spider mite and can be easily seen with the unaided eye. Legs and mouthparts are pale in contrast to a red or dark green body. The body is round with the first pair of legs almost twice as long as the others. Clover mite eggs are spherical, dark red, and lack a thread-like stipe.

Damage to leaves may be composed of lines of feeding spots resembling a scratch on the upper surface. On turf grass, the damage may give a silvery cast to the turf, especially in Spring.

Biology

Adult mites are rusty brown to dark red in color and smaller than the head of a pin. The front legs are longer than the body. Immature stages are bright red. This mite can reproduce without mating and large populations can develop quickly. Clover mites breed and feed in grasses, clovers and lawns surrounding homes and buildings. There have been reports of Bryobia damage to impatiens and lobellia. The worst infestations are often reported in new lawns and lawns that have been heavily fertilized. Differing weather patterns seem to elicit differing behaviors or different Bryobia species. Clover mites are a "cool-season mite". They seem to be most numerous in the Spring, but may also be abundant during the Fall or on warm days in the Winter. They may also become a problem during a period of drought as they become mobile while the turf dries out. In the late Fall, clover mites may congregate around foundation walls and other surfaces. They will be quiet and unnoticed during hot summer and cold winter, but crawl and become active again in the Spring as temperatures warm.

Control

Outdoors- If clover mites become a problem or are a routine problem, the lower three feet of foundation or outside wall may be sprayed with with a pesticide containing cyfluthrin or fluvalinate. Treat around any entry points. The surrounded lawn may also be sprayed six to ten feet from the building. Two or three sprays may be needed at two-week or three-week intervals. Malathion may be used, however, there have been reports in Poland of resistance by this mite to organophosphates. Caulking and weatherstripping may also help create a physical barrier around windows, doors and cracks. Buildings with grass growing up to the foundation often have more mites entering. Do not over-fertilize turf.

Indoors- After mites have entered a building they will not survive for long. Generally, it would be better to confine any chemicals to the outside perimeter of the building or threshold and rely on frequent vacuuming and patience, rather than using household insecticides.

Useful References-

Jeppson, L.R., H.H. Keifer, and E.W. Baker. 1975. Mites injurious to economic plants. Univ. Calif. Press. Los Angeles. 614. pp.

Lehman, R.D. 1982. Mites (Acari) of Pennsylvania conifers. Trans. Amer. Entomol. Soc. 108:181-286.

Recommendations of specific chemicals are based upon information on the manufacturer's label and performance in a limited number of trials. Because environmental conditions and methods of application by growers may vary widely, performance of the chemical will not always conform to the safety and pest control standards indicated by experimental data.

Recommendations for the use of chemicals are included in this publication as a convenience to the reader. The use of brand names and any mention or listing of commercial products or services in this publication does not imply endorsement by the North Carolina Cooperative Extension Service nor discrimination against similar products or services not mentioned. Individuals who use chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage and examine a current product label before applying any chemical.

Other Resources

• Back to Insect Notes
• Horticulture Information Leaflets(HILs)
• Plant Disease Notes
• North Carolina Agricultural Chemicals Manual
• North Carolina Cooperative Extension Service

Prepared by: S. Bambara, Extension Entomologist. Mite photo courtesy Allinda Huffman.

Published by North Carolina Cooperative Extension Service

Distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. Employment and program opportunities are offered to all people regardless of race, color, national origin, sex, age, or disability. North Carolina State University at Raleigh, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating.

ENT/ort-124     January, 2003

Web page last reviewed January, 2008 by the webperson.