Chiggers – Just Scratching the Surface

Chiggers are the parasitic immature stage of a mite that feeds as an adult on other arthropods. Chigger bites are lingering “souvenirs” of time spent in brushy areas or tall grass. Chiggers are too small to see (1/150 inch long) and you will not feel them until several hours after they have fed and dropped off. The following information is intended to reduce your problems with them.

Figure 1. Six-legged chigger larva (1/150 inch long). (Photo: Hansell F. Cross, Georgia State University, Bugwood.org)

Figure 1. Six-legged chigger larva (1/150 inch long). (Photo: Hansell F. Cross, Georgia State University, Bugwood.org)

How do chiggers find us?

Like hungry ticks, chiggers crawl up tall grass blades or other “stick-ups” and wait to sense CO2 or other cues given off by an approaching host. They climb onto the unwary passer-by and wander in search of a tender place to feed. Chiggers are not good at hanging on so they settle at wrinkles or skin folds (behind the knee is an ideal place), or where clothing is tight (waistbands, sock tops, etc.) (Figure 2). A hair follicle or skin pore gives them a place to feed (Figure 3).

Figure 2. Common chigger bite sites (Photo from “The Bed Bugs Handbook”)

Figure 2. Common chigger bite sites (Photo: “The Bed Bugs Handbook” at http://www.blackburnnursery.com/chiggers1.html)

Why do chigger bites itch?

Chiggers do not burrow into skin, nor do they suck blood. They feed on skin cells that are liquefied by their digestive enzymes. Our skin reacts to these foreign enzymes, causing bite sites to become red and swollen. Irritation begins 3 to 6 hours after chiggers have stopped feeding. These angry welts can itch intensely for several days. In addition, frequent scratching can result in infection and a compounding of problems.

Figure 3. Chigger feeding at hair follicle (Photo: “Chiggers” HYG-2100-98, The Ohio State University)

Figure 3. Chigger feeding at hair follicle (Photo: “Chiggers” HYG-2100-98, The Ohio State University at http://www.blackburnnursery.com/chiggers1.html)

What will relieve the itching?

Topical lotions or creams applied to affected areas, such as calamine lotion or corticosteroid creams, may provide some relief. Oral Benadryl and other antihistamines also may help. Home remedies to “suffocate” the mite (such as, applying clear nail polish, rubbing alcohol, or bleach) are of no benefit and may be harmful. See your physician if the irritation lingers or intensifies.

How do I protect myself?

The best strategy to avoid the miseries of chigger bites is to stay out of “chigger territory” or to be prepared if you have to go there. Enter their domain at your own risk.

  • Wear long loose-fitting pants tucked into boots or socks to keep chiggers on the outside of your clothing
  • Do not sit or lie directly on the ground in or near overgrown areas.
  • When possible, walk in the center trails, not along margins.
  • Use an insect/tick repellent. Products containing diethyl toluamide (DEET) or permethrin (clothing only) are most effective. Be sure to read and follow directions.
  • Take a hot, soapy shower immediately after coming indoors; vigorous scrubbing can remove many chiggers before they start to feed.

What can I spray to get rid of chiggers on my property?

  • Regular mowing and brush removal takes away the protective cover that small mammal hosts of chiggers need. It also allows sunlight to penetrate the area and lowers humidity. It is long-term management solution.
  • Insecticide sprays may provide some temporary reduction of significant chigger problems if directed into areas where chiggers and their animal hosts hang out. This is only a short-term solution while habitat modifications are being made. Read the product label carefully to be sure the site you are planning to treat is on the label. Look for specific instructions that will increase chigger control.

 

By Lee Townsend, Extension Entomologist

 

 

Posted in Human Pests