Itchy Chiggers! (008)
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Itchy Chiggers!
by Barb Ogg, PhD, Extension Educator
Chiggers are the larvae of the harvest mite, Trombicula alfreddugesi. The eight-legged adult harvest mites are bright red and are seen crawling over the soil surface when one is spading the garden during the warm days of springtime (photo right). They look like small velvety red spiders. In the early spring, these adult mites lay eggs in the soil that hatch into the larval chigger stage.
The adults and most immature stages are completely harmless, but the tiny, six-legged larval stage is parasitic on many animals, including rodents, birds, poultry, rabbits, livestock, snakes, toads, as well as humans. The larval chigger moves very quickly on the ground and crawls onto feet or legs. On its host, the chigger usually moves about until it reaches a place where it is somewhat confined, such as around ankles, under socks, or behind knees. when people sit on chigger-infested ground, frequently they may get severe chigger bites around the waistline or in the crotch area, especially under belts and elastic bands of underwear. Sometimes chiggers may move to the upper torso and attack the armpits. Chiggers become active in June, but outdoor activities and warm days around the Fourth of July result in increased complaints about chiggers.
Contrary to popular belief, chiggers do not burrow into the skin, but pierce the skin, (often around a hair follicle) and inject a fluid that prevents blood from clotting.The fluid causes tissues to be inflamed; each bite has a characteristic red welt with a white, hard central area. The tiny red chigger in the center of the itching bump is effectively camouflaged by the inflamed tissues. Fluids secreted by the mite iquifies the tissues that are ingested by the chigger. It is these injected fluids that results in the severe itching and dermatitis that accompanies chigger bites.
After becoming fully fed, the chigger drops from its host, goes into the ground and enters a quiescent stage. In the fall of the year, it becomes a bright red adult that overwinters.
University of Nebraska-Lincoln Extension in Lancaster County is your on-line insect pest and wildlife educational resource. The information on this Web site is valid for residents of southeastern Nebraska. It may or may not apply in your area. If you live outside southeastern Nebraska, visit your local Extension office
Contact Information
University of Nebraska-Lincolnin Lancaster County
Web site: lancaster.unl.edu
444 Cherrycreek Road, Suite A,
Lincoln, NE 68528
| 402-441-7180
Control:
You can check out whether an area is infested with chiggers by using a simple technique. Six-inch squares of black paper placed vertically in the grass will become covered with chiggers if they are present. Because several hours elapse before chiggers settle down to bite, bathing soon after exposure to chigger-infested areas may wash chiggers off your body and prevent feeding. Clothing also should be washed to prevent reinfestation.
The most suitable breeding areas of chigger mites are among weeds and thick vegetation are where there is an abundance of moisture and shade. Good weed control with herbicides or mowing and elimination of excess shade will help reduce the number of chiggers in an area. Around homes, close cutting of lawns will prevent favorable breeding sites and reduce populations.
Insect repellent containing "deet" (diethyltoluamide) is effective in reducing attractiveness of your body for chigger feeding. For maximum effectiveness, repellents should be applied to shoes, socks, pant cuffs, ankles and legs, and around the waist. To relieve itching of chigger bites, over-the-counter lotions and ointments may be helpful. The "painting" of bites with clear nail polish to destroy the chigger is probably not effective. By the time the bite itches, the chigger has already fed and dropped off.
Outdoor areas where chiggers are known to be a problem can be sprayed with an appropriate insecticide labeled for chigger control. Sprays should be made on grass, ground litter and soil, and shrubbery when chiggers start to become a problem in June and July. Be sure to follow label directions of any repellents or insecticides that are used.
The tiny larval chigger mites do not present a real medical health concern, but they can make enjoyable outdoor outings into an unpleasant experience that lasts several weeks. Many people have found that chigger bites are the most irritating and long-lasting bites by summer arthropod pests.
(NOTE: If you are not sure what is causing bites, or need information on biting pests found in your area, contact your local university extension office. Find your office HERE. If you are concerned about the bite or possible infection, always contact your physician.)
