Chiggers are the larval stage of certain mites, often too small to be seen without magnification. These tiny, six-legged organisms are known for causing intensely itchy red welts when they attach to humans and animals.
Geographic Hotspots in the US
Chiggers are widely distributed across the United States, but their presence is particularly notable in a region often referred to as the “chigger belt.” This area predominantly includes the southeastern, midwestern, and south-central parts of the country. States such as Texas, Oklahoma, Missouri, Arkansas, Louisiana, Mississippi, Alabama, Georgia, Tennessee, Kentucky, and the Carolinas frequently report significant chigger activity.
The warm, humid climates in these regions provide ideal conditions for chigger reproduction and survival. Their populations are less prevalent in drier, more arid western states, at higher elevations, and in cooler northern states due to unfavorable environmental conditions that limit their life cycle.
Even within the “chigger belt,” their distribution can be localized, with some areas having dense populations while others nearby have very few. This variability is often tied to specific microclimates and vegetation types. The overall geographic pattern indicates a preference for the warmer, more humid climates found in the central and eastern United States.
Preferred Habitats and Environments
Chiggers thrive in specific outdoor environments that offer a combination of moisture and protective vegetation. They are frequently encountered in areas with tall grasses, overgrown fields, and dense weeds. These mites also inhabit the edges of woodlands, where shade and humidity are higher.
Berry patches are another common location for chiggers, with thick undergrowth and moisture retention. Moist ground, leaf litter, and decaying organic matter provide suitable conditions for chigger development. Any place with dense vegetation that offers both shade and consistent humidity can harbor chigger populations.
Chigger larvae climb onto the tips of grass blades or other low-lying plants, waiting for a host to pass by. They remain close to the ground, less than a foot high, making them easily picked up by people or animals brushing against the vegetation.
Seasonal Activity
Chigger activity is dependent on temperature and humidity, making them seasonal across the United States. They are most active during the warmer months, from late spring through summer and into early fall. Peak activity occurs when ground temperatures range between 77 and 86 degrees Fahrenheit.
As temperatures drop, chigger activity decreases significantly. They become dormant or die off when temperatures fall below 42 degrees Fahrenheit. Adult chiggers overwinter in the soil or protected spots, emerging in the spring to lay eggs as conditions become favorable. Prolonged periods of warm weather can extend their active season, allowing multiple generations to emerge throughout the year in suitable climates.