MDC says oak leaf itch mites still pesky in west Missouri

Oak leaf itch mites are tiny arachnids that can cause a bite similar to a chigger.

Kansas City, Mo. – A word of caution before you leap into a pile of raked up oak tree leaves this fall. The nearly microscopic oak leaf itch mite could cause some bites similar to those left by chiggers. The insect-like mites were an irritating pest in some areas of western Missouri, Kansas and Oklahoma in late summer and autumn. Some may be lurking in oak leaves that have fallen to the ground, said Rob Lawrence, forest entomologist for the Missouri Department of Conservation (MDC).

   Cold weather, especially hard freezes, will halt the mites. But if weather remains on the warm side, those raking and handling oak tree leaves may want to take a few precautions: shower or bath after working in the leaves and launder work clothes promptly.

    An itch mite bite is similar to a chigger bite, but it has a slightly different appearance. The itch mite bite often has a raised, blister-like center that can become itchy and painful when scratched.

   The oak leaf itch mite is believed to have originated in Europe. It was first recognized in the United States when it was found in Kansas in 2004 and then later found in other states. The mite occurred at outbreak levels in 2004-2006, Lawrence said.  It has been mostly absent since then until reappearing in Kansas last year. A severe freeze in April, 2007, resulted in a widespread kill of early spring foliage. That may have directly killed the itch mites or the prey they feed upon, an insect called the marginal fold gall midge.

   The gall midges may be increasing and thus supporting a larger population of oak leaf itch mites. But itch mites will also feed on other insects. That may include eggs of the periodical cicadas that appeared in the Kansas City region this year. However, Lawrence said there are reports of itch mites in southwest Missouri where periodical cicadas did not emerge.

   MDC supports healthy urban forests. For more information, visithttp://on.mo.gov/1MmqTUq.