You Are Here: Management Updates 2004 Archive June 15, 2004

Date: June 15, 2004
Category: Insects
Subject: Annual Bluegrass (Hyperodes) Weevil, White Grubs, Caterpillars, Chinchbugs, Billbugs

For golf course superintendents, the annual bluegrass weevil (Hyperodes weevil) continues to be the number one insect headache right now. We have just returned from Westchester County, NY. About half of the insects we found in the plugs were adults. Many of the adults were "callow", rusty brown in color. Some are black on the back and still a little rusty colored on the belly. Callow adults are the new ones emerging from the first generation. Normally they take a few days to start mating and laying eggs. Meanwhile the other half of the individuals we found were large larvae or pupae, although there were a couple smaller larvae as well.

Samples taken from a golf course in the Connecticut River valley near Amherst (taken yesterday) revealed mostly large larvae and pupae. New adults have not yet appeared at that location. So western Massachusetts seems to be about a week behind Westchester County, which is pretty typical for this time of year.

As we have said repeatedly this spring, scouting and keeping track of the stages of development will be particularly important this year. The "recipe" we use, a salt soak developed by Nancy Consolie last year when she was working in Dan Peck's lab at Cornell (Geneva), involves about 3/4 cup of salt (table salt is fine, or agricultural salt is even cheaper) in a quart of lukewarm water. Cut samples that are about two inches in diameter or two inches square, break them apart gently, and put the material in a small bowl. Fill the container with the salty water. Most larvae, pupae, and adults will float to the surface within 15 to 30 minutes.

Based on our observations from Westchester County, we are getting close to the time to apply a material targeting the new young adults. In this case, you want something that will stay in the thatch - for example, a pyrethroid or Dursban™. Water in lightly - one or two passes of the head should do it unless it has been unusually dry when you make the application.

Grubs
We have had reports of European chafer adults flying, particularly in eastern Massachusetts. These beetles are slightly larger than Japanese beetles and a tan color. They normally begin to fly, sometimes in very large numbers, just as the sun is setting. In addition I have seen adult asiatic garden beetles in the soil in my own flower beds. Finally, I saw oriental beetle adults this morning in Westchester County. So the beetles are pretty much on schedule. This is the time to start thinking about how you plan to manage the upcoming grub problems that may arise as a result of the adult activity.

Caterpillars
We have had reports of black cutworm activity on golf courses, and I have seen sod webworm adults flying in my own lawn. Remember that webworms seldom cause enough damage in lawn settings to warrant treatment. Often what happens is a lawn succumbs to drought stress (later in the summer), but when a turf manager comes in to take a look and place the blame, the caterpillars are accused of causing the damage. As Dave Shetlar (Ohio State University) points out, webworms usually are not the cause of the problem, drought is.

Others
We have not yet had any reports of chinchbug or billbug activity. However, this is the time of year when adults are active and laying eggs. Scouting would be a good idea - identify the chinchbug and billbug "hotspots" before they develop into damaging populations.

- Submitted by: Dr. Pat Vittum