The microscopic itch mites prey on small fly maggots which cause “leaf edge" galls on pin oak leaves. The galls on pin oak leaves have been unusually abundant in recent years. When the maggots mature, they emerge from the galls, drop to the ground and pupate for the winter.



When numbers of the gall gnat larvae decline, either through predation or by evacuation from their galls, the hungry itch mites crawl about on foliage or bail out of the trees into wind currents to find other suitable hosts.

Preliminary research indicates that 16,000 adult female itch mites (potential biters) can emerge from one infected oak leaf and fall to the ground. Entomologists estimate there are most likely millions of mites floating down from affected oak trees.

The mites inject a highly-potent neurotoxic venom into their insect prey through their needle-like mouthparts and voraciously consume their prey.

Adult females are unique among living animals in that they deposit their eggs into a pouch, or ovisac, formed at the tip of their abdomens. A mated female attaches to an insect host and enlarges to 1/16 inch -- about BB size. The female nurtures her brood directly from the egg stage to adulthood (no nymphal stages). As many as 300 mites can develop within the female’s enlarged abdomen!

With a population doubling time of two days, Pyemotes mites can number in the millions in a short period of time.

There is no pain when these mites bite. In fact, most people are unaware that they have been bitten until the next day, when quarter-size reddened welts appear with a pimple on their center. The bites are most commonly distributed over the neck and shoulders and on the upper torso where clothing hangs loosely. They appear after people have been involved in outdoor activities.

“The bites we are seeing do not pose a major health threat – they mostly cause an annoying, intense itch," Dr. Eric Whitaker, director of the state public health department, said in a statement. “Do not scratch the bites, however, or you could cause an infection, which would create other health problems.

Entomologists at Kansas State University reported bites on dogs and cats as well as on humans during outbreaks.

Some bite sufferers find their own way of dealing with the outbreak including over-the-counter remedies and chemicals. Various state officials have recommended antihistamines and lotions. With the growing concern over the earth and holistic health, may others are seeking all natural remedies including new electrolyzed oxidizing water technology for healing.

This problem is not just restricted to Chicago. Any Midwest state with pin oak trees can suffer from these outbreaks. Past states have included Kansas, Missouri, Nebraska and Texas. Itch mite season runs from now through November.