This year annual bluegrass weevil development on golf courses has been asynchronous and choosing the right timing for applications has been challenging. Unusually wet weather conditions with periods of cooler temperatures in the spring resulted in a prolonged egg laying period. Even though for the most part the spring generation has completed its development, and predominantly we observe new adults and small larvae of the summer generation, we still see late larval instars of the first generation. All ABW life stages have been found in recent samples. It is important to monitor larval development and be ready for a larvicide application to manage second generation larvae this or next week.
This week we saw a report from a colleague (Mike Raupp) in Maryland, mentioning that they were seeing a lot of grub activity this year. While it is still a little early to worry about grub damage in southern New England, adults of the various species (European chafer, oriental beetle, Japanese beetle, asiatic garden beetle, and even the occasional masked chafer) are flying now, and many are already laying eggs. Remember that the best time to apply a neonicotinoid to target white grubs is "when the adults are laying eggs". So if you are planning to use a neonicotinoid for grub control this year, now would be a good time to do it. It is too late to get optimum control from chlorantraniliprole, but cyantraniliprole remains an option for reducing grub populations. Whatever you use, be sure to water it in!
Another colleague (Rick Brandenburg, at North Carolina State University) reported that they are already seeing activity of fall armyworms, about a month earlier than usual. While we do not usually see much damage from fall armyworms in southern New England, the potential is always there. So keep an eye out for them in the coming weeks.
Meanwhile all the rain that fell in the spring (more than 9 inches in Amherst in April, about three times more than normal) resulted in some shallow, weak rooting in turf throughout the region. That means that, as the hot weather descends upon us, turf will be less able to withstand feeding damage from chinch bugs and billbugs. Reports of severe damage from bluegrass billbugs were received during past few weeks. The best timing for application against billbugs is June – beginning of July, when young billbug larvae are actively feeding. Older billbug larvae are large and hard to manage, but several options for curative control are available.
Submitted by: Dr. Olga Kostromytska and Dr. Pat Vittum
