Chiggers are microscopic mites belonging to the arachnid family, related to spiders and ticks. Only the six-legged larval stage is parasitic to humans and animals. Since Texas’s climate is highly conducive to their life cycle, understanding when these pests are active is important for anyone who spends time outdoors. This article defines the chigger season in Texas and provides steps for prevention and relief from their intensely itchy bites.
Understanding Chigger Activity Based on Temperature
Chigger activity is governed by ground temperature and humidity, not fixed calendar seasons. Peak activity occurs when temperatures are consistently warm, specifically between 77°F and 86°F. This means the season typically begins in late spring (May or June) and continues through the summer and early fall months.
The season often runs until late September or October, though activity can continue year-round in warmer, southern regions. Chiggers become inactive below 60°F, and the larvae die below 42°F. A sustained cold snap effectively ends the chigger season.
Larval chiggers hatch continuously once the ground warms to about 75°F. They are most active in dense vegetation, tall grass, and high humidity areas. They climb onto vegetation, waiting just inches off the ground to latch onto a passing host.
Identifying Chiggers and Their Bites
The larval chigger is tiny, measuring less than 1/150th of an inch, and is nearly impossible to see without magnification. These mites are yellowish to light-red in color and are the only life stage that feeds on a host. Chiggers do not burrow into the skin or consume blood.
When a chigger attaches to a host, it injects a digestive enzyme through its sharp mouthparts. This enzyme breaks down skin cells, which the chigger consumes as a liquid. The body’s immune response causes the surrounding tissue to harden, forming a tube called a stylostome through which the mite feeds.
Intense itching typically begins within three to six hours of the bite, resulting from the body’s allergic reaction to the digestive enzymes. Symptoms are red welts or pimple-like bumps that may progress to blisters. Bites are often found in clusters where clothing is tight, such as the waistline, ankles, behind the knees, and the groin area.
Strategies for Prevention and Bite Relief
Preventing chigger bites involves creating barriers and using repellents when entering wooded or grassy areas. Wearing long pants and long sleeves, especially when tucked into socks or boots, helps keep the mites from reaching the skin. Permethrin, a synthetic insecticide, can be applied to clothing and gear for long-lasting protection.
Repellents containing DEET (N,N-diethyl-meta-toluamide) should be applied to exposed skin and around clothing openings, following label directions. Since chiggers prefer dense vegetation, keeping lawns mowed short and trimming back brush around the home reduces their habitat. Avoiding sitting directly on the ground also reduces exposure.
If exposure is suspected, take a warm, soapy shower immediately after coming indoors. Scrubbing the skin vigorously with a washcloth can dislodge any unattached chiggers. Treatment focuses on relieving symptoms. Over-the-counter options such as calamine lotion, hydrocortisone creams, or oral antihistamines help manage intense itching. Applying a cold compress provides temporary relief.