You Are Here: Management Updates 2004 Archive May 28, 2004

Date: May 28, 2004
Category: Insects
Subject: White Grubs, Annual Bluegrass (Hyperodes) Weevil

We collected some white grubs from Berkshire County (western Massachusetts) the other day and noticed that most of the European chafer grubs had stopped feeding. Some had already moved into that elusive "pre-pupa" stage, where they begin to change shape a little bit. Almost all of the grubs had stopped feeding, and looked a little yellower than we usually see. This simply means that they will be pupating soon, and adults should be emerging about on schedule or slightly earlier than the usual mid-June.

Japanese beetle grubs appeared to be on schedule - still feeding and looking very healthy. They should be feeding for another couple weeks before they go through the same process (emptying their digestive system of undigestable food and preparing to pupate).

We have received several phone calls from superintendents throughout southern New England, confirming that the annual bluegrass weevil (Hyperodes weevil) larvae are quickly becoming active. Keep in mind that the initial damage often resembles anthracnose, so if you see anthracnose-like symptoms, take the time to take a closer look. If you see those tell-tale "grains of rice with brown heads", active in the thatch and near the crowns of the plant, you'll know you have Hyperodes weevil larvae. Right now my guess is that summer activity will be accelerated, so we may be looking at three or more generations in the metropolitan area and three generations in much of southern New England.

Good luck in your weevil scouting - the cooler weather forecast for the holiday weekend will slow their development just a little bit.

- Submitted by: Dr. Pat Vittum