You Are Here: Management Updates 2002 Archive May 15, 2002

Date: May 15, 2002
Category: Insects
Subject: Armyworms, White Grubs, Hyperodes Weevils

Armyworms
We have checked with colleagues in states south of here, and so far there have been no reports of unusual armyworm activity. Will Hudson (Georgia) and Rick Brandenburg (North Carolina) confirmed that they had not seen any unusual activity in their states so far this spring.

However, Chris Williamson (my colleague at the University of Wisconsin) confirmed that large numbers of armyworm adults were trapped in southern Wisconsin the week of 6 May. We are not sure what this means yet, and it is most likely that the armyworms in Wisconsin came north from states directly south of Wisconsin. (It is not unusual for the states in the upper Plains to see high armyworm populations, normally attacking field crops.)

So at this point, we are in a "wait and see" mode for armyworm activity in New England for 2002. Remember that many areas in New England last year apparently experienced an increase in parasitic wasps that attacked the caterpillars, and we can hope that the wasp numbers may be higher than usual this spring, but at this point we are just guessing what will happen this year.

White Grubs
It is too late to try and control most white grub infestations in New England now. European chafers will finish feeding within the next couple weeks, and then will pupate. Adults normally emerge in mid June (night fliers, especially active at twilight). Japanese beetles will continue feeding for about four more weeks. Now would be a good time to map grub activity, if you haven't already done so, and plan on targeting the same areas in July or August if damage was severe last fall or this spring. In about eight years out of ten years, the same areas tend to be attacked.

Annual Bluegrass Weevils (Hyperodes Weevils)
We are mightily confused! The spring weather has led to some unusual weevil activity. Some adults were on the move during the hot weather in mid April but apparently slowed right down again. However, we have found tiny larvae in the turf at a site in Danbury, CT, which suggests that in some areas, the weevils are right on target for their development.

Areas in southern New England and metropolitan New York should start watching for the telltale signs of wilt, perhaps as early as the last week of May and certainly during the first week of June. Other areas further north will probably experience damage somewhat later. It is too late in most locations to apply a preventive material (targeting adults), but be on the look-out for larval activity and respond accordingly.

Incidentally, Dr. Jennifer Grant (Cornell IPM Program) and I put out a field test yesterday in Yonkers, NY, applying some nematodes that had initially been recovered from annual bluegrass weevils on a golf course on Long Island. We'll keep you posted - we should be sampling those plots in mid June and will have an idea then whether the nematodes worked.

- Submitted by: Dr. Pat Vittum