You Are Here: Management Updates 1999 Archive June 25, 1999

Date: June 25, 1999
Category: Insects
Subject: Hot Temperatures, Beetle Adults, Billbugs

The real story in the insect world is the weather - as hot temperatures stress turf, insect activity becomes more apparent. Right now (25 June) we are in a waiting game with many insects - the annual bluegrass weevil (aka Hyperodes weevil) is just finishing its first generation and young adults can be seen moving on the surface of tees and putting greens. Treatments directed toward the second generation should be made between 28 June and 9 July - earlier if you are in warmer locations, later if in cooler locations. (Note that some pyrethroids are sensitive to high temperatures, so if you are using one of the pyrethroids, you should be careful to make the applications early in the day before the heat starts in again.) Whatever you use, water in VERY LIGHTLY - just enough to get the material off the blades.

Japanese beetles are flying - I saw my first ones yesterday. So they are about a week ahead of schedule. Watch for beetle feeding on sensitive ornamentals (crabapplies, purple leaf plums, lindens, and the like come to mind!). Normally females would start laying eggs about two weeks from now, but when soils are very dry, females seem to delay egg laying. While it is too early to tell, it certainly seems like we may be in for a long hot summeer - but that might work to our advantage with Japanese beetle eggs and grubs.

Billbugs may start showing up any time now. Billbug damage closely resembles drought - so before you assume that "droughty" looking patch is just water stress, poke around a bit. Billbug larvae are typical weevil larvae - no legs, cream colored with brown heads. Early in their development they will be in the upper part of the thatch but as they feed and grow, they will move down into the thatch, and even to the roots. If you grab a small tuft of grass between thumb and forefinger and tug sharply, healthy turf will resist or will break off at the blades, while billbug-weakened turf will break off much lower, where the larvae are feeding.

- Submitted by: Dr. Pat Vittum