Annual bluegrass weevil (ABW) larvae are starting to show up in fairly high numbers in untreated areas that are part of our monitoring program with Syngenta's Weevil Trak program. One site near Albany had large numbers of fifth instars, while a site east of Springfield had primarily third and fourth instars. The population was high enough in both sites that we should have seen some damage, but damage was in fact barely noticeable. Both of these sites have already passed through the "time to apply a larvicide", and have accumulated more than 400 growing degree days.
My guess is that the unseasonably cool temperatures and steady rains (2.5 inches in Amherst over the past 36 hours, for example) are slowing development this spring. And the moist soils are probably masking damage. Many of you in higher elevations are in the Weevil Trak Stage 3 (apply larvicide) now, and I noticed over the weekend that Rhododendrons are still in full bloom in many parts of northern Massachusetts and southern New Hampshire. If you have not already applied your larvicide (e.g., cyantraniliprole, indoxacarb, spinosad, trichlorfon), you probably should do so as soon as the soils dry out a little bit.
So for those of you who have had ABW damage in past years, pay close attention this weekend. The temperatures are forecast to shoot into the low 90s on Monday and Tuesday, and the turf will not have had a chance to adjust to such high temperatures so rapidly. If we do not get much rain, turf may show some stress in that heat - and a little bit of ABW nibbling could be enough to cause visible damage.
Don't let your guard down - monitor your usual hot spots and keep a curative product on hand in case you see some larval activity.
Submitted by: Dr. Pat Vittum