Annual bluegrass weevil
For several years we’ve experienced rather mild and snowless winters in the region. This made the winter of 24-25 feel harsh, even though the winter and this spring have been close to "normal" according to average temperatures, GDD data and weevil activity. There was a slow and steady accumulation of degree days starting from the second week of March. GDD accumulations (base 50°F) are not very different across Massachusetts and are around the range of 48-54 right now. The eastern part of the state is slightly behind (41 GDDs). The Cape Cod location that we are monitoring this year (Sandwich, MA) has accumulated only 25 GDDs so far.
We have been monitoring weevil activity since early April. ABW adults started appearing on short grass only recently (a few days ago). We also observed them in pitfall traps installed in roughs. Forsythia is now in full bloom or close to full bloom, and therefore it’s time to start monitoring adult activity. Soap flushes, vacuuming, visual inspections of greens, and checking clipping buckets after mowing greens can be used to detect peak adult density. If pitfall traps are installed, pay attention to daily catches to determine the peak. Monitoring adult activity is a great investment of time and effort even if an adulticide application (pyrethroids and novaluron are recommended during this time) is not in your plans. Peak adult activity is a reference point for early larvicide application (anthranilic diamides and novaluron are recommended at this time), which ideally should be scheduled 1-2 weeks after peak adult activity.
Remember that even if you start seeing adults on the surface, resist the temptation to use an adulticide before that magical Forsythia "half green - half gold" timing, when adults are peaking. This year, we expect adult activity to peak during the last week of April. Adult activity is most likely to pick up with warmer temperatures during the following couple of weeks. According to the forecast for the next two weeks for much of southern New England, we are expecting a significant warm up, which will result in increased GDD accumulation.
Other insects
Damaging chinch bug and billbug populations have become more frequent during the past several seasons. Dry and hot weather favored high chinch bug populations during the 2024 season, and we have observed significant turfgrass damage caused by chinch bugs (Figure 1.) This spring is relatively cool and wet, and in addition winter was very cold. These conditions might have caused significant natural mortality of chinch bugs. However, it is still important to monitor chinch bug populations, especially if severe damage was observed in previous years. We have been monitoring chinch bug activity using vacuuming and pitfall traps. During the first week of April, we observed active adult chinch bugs in our samples for the first time this season. Nymphs are expected to appear and peak by the end of May.
Billbugs are expected to show up in May with adult activity peaking during the last week of May. But as of now they are not active yet.
White Grubs
Soil temperatures have reached 50°F, therefore it is expected that grubs will start moving closer to the surface and resume feeding soon. Spring treatments are not commonly advised, even though some damage might occur… unless it is absolutely necessary to stop the damage. After a short period of feeding, many grubs quickly transform into prepupa stage, during which they do not feed (and are not likely to cause damage). Prepupae and pupa are also not susceptible to insecticides. Additionally, spring grubs are large and resilient, and very few chemicals can be adequately effective against them. The best approach is to schedule a plan of action to manage the 2025 generation of grubs in the summer (unless you are planning to use chlorantraniliprole, which in that case should be applied between mid-April and early June).
Finally, please let us know your opinion regarding the insect management issues that are important for you by participating in a survey.
Turfgrass entomologists from multiple states (KY, MA, NC, NJ, OH, PA, VA) are proposing a collaborative research project to address the needs of stakeholders in the turf industry. This survey will help identify the top priorities of your concerns in managing turfgrass health. It takes on average 5-6 min to complete the survey.
Please use the QR code or the link below:
https://go.osu.edu/turfgrass_pest_survey
Submitted by: Dr. Olga Kostromytska