Common Names: Chigger, Redbug
Scientific Name: Order Arachnida, family Trombiculidae, Trombicula spp., Entrombicula spp.
Identification: Microscopic animals related to ticks and spiders. Larvae are bright red.
Biology and Life Cycle: Nymphs hatch in the spring and are parasites on humans and animals. They inject a digestive juice that dissolves skin cells so they can be more easily eaten. Affected skin will redden and swell. Their numbers are the highest in mid-summer. The adults feed on insects.
Habitat: Grasslands and weedy unirrigated areas.
Feeding Habits: Nymphs attach to skin of various animals to feed.
Economic Importance: Cause severe itching and small reddish welts on skin.
Natural Control: Increased soil moisture. Some researchers say chiggers have no natural enemies. That may be true, but the imported fire ants will certainly eliminate them.
Organic Control: Sulfur dust is a good repellent. So is lemonmint, also called horsemint (Monarda citriodora). Take a hot, soapy bath to remove larvae. Stop the itching with baking soda, vinegar, aloe vera, or comfrey juice.
Insight: If you have to walk through property that's dry and weedy and it's summertime, take a few precautions. First, don't wear shorts. Second, dust your shoes, pant legs, and socks with powdered sulfur. It's available at any nursery or feed store. Rubbing the crushed flowers of lemonmint on your clothing will also repel chiggers.
Chiggers can be controlled with a broadcast application of diatomaceous earth or an application of granular or dusting sulfur at 5 pounds per 1,000 square feet. If you have alkaline soil, the sulfur is also a good soil amendment. If you have acid soil, just don't overdo it. Excess sulfur will kill or severely imbalance the microorganisms in the soil. If your property is watered occasionally, chiggers won't be a problem.
We know one outdoorsman who swears that if you don't wear underwear or socks, the chiggers won't have a place to hide and won't bother you.