Chiggers are tiny mites that can cause irritating, intensely itchy bites. Understanding how temperature impacts their survival provides practical knowledge for effective control and managing their presence around outdoor spaces.
What Are Chiggers?
Chiggers are the larval stage of specific mites belonging to the Trombiculidae family, making them relatives of spiders and ticks. These six-legged larvae are nearly microscopic, typically measuring between 0.15 to 0.3 millimeters, making them difficult to spot without magnification.
They thrive in outdoor environments, particularly in grassy or wooded areas, tall weeds, and other dense vegetation. Chiggers prefer warm, humid conditions, which makes them especially active during late spring, summer, and early fall.
Contrary to common misconception, chiggers do not burrow into the skin or feed on blood. Instead, they attach to a host, inject digestive enzymes that break down skin cells, and then feed on the liquefied tissue through a hardened feeding tube formed by the host’s skin. This enzymatic action results in the characteristic itchy, reddish welts that appear hours after exposure.
Temperature’s Lethal Effects on Chiggers
High temperatures are highly effective for eliminating chiggers, especially from clothing and fabrics. Temperatures above 120°F (49°C) are typically lethal to these mites. A standard hot water wash cycle, followed by a high-heat dryer cycle, is usually sufficient to kill chiggers on infested garments.
The heat from a clothes dryer is often more critical than the wash water’s heat for ensuring chigger eradication on clothing. Placing items in a dryer on high heat for at least 25 minutes can effectively kill any lingering mites.
Freezing temperatures also prove lethal to chiggers, though this method is less practical for large-scale application. Chiggers become inactive when temperatures drop below 60°F (16°C). They will die when temperatures consistently fall below 42°F (5.5°C). Larval chiggers, eggs, and nymphs typically do not survive temperatures below 47°F (8°C). While cold can be effective for smaller, non-washable items that can be placed in a freezer, heat treatment remains the most convenient and practical method for decontaminating clothing and fabrics.
Comprehensive Chigger Control
Preventing chigger exposure involves adopting several protective measures when outdoors. Wearing long-sleeved shirts and long pants, especially when tucked into socks or boots, creates a physical barrier against these mites. Staying on cleared paths and avoiding tall grass, dense brush, and thick vegetation significantly reduces the likelihood of encountering chiggers.
Applying insect repellents offers another layer of protection. Products containing DEET can be applied to exposed skin or clothing to deter chiggers. Permethrin-based repellents are designed for application to clothing and gear, bonding to fabric fibers for long-lasting protection, often effective through several washes.
Immediate post-exposure hygiene is important if you suspect chigger contact. Showering with soap and water as soon as possible after being outdoors can wash off any unattached chiggers before they feed. This simple step can prevent the development of itchy bites.
Managing the environment around your home can also deter chiggers. Regularly mowing lawns short, removing tall weeds, and clearing brush and leaf litter reduces the moist, shady habitats that chiggers prefer. A multi-faceted approach, combining personal prevention, immediate hygiene, and environmental control, offers the most effective strategy for minimizing chigger bites.