After a long, snowy and brutally cold end to the winter in many parts of the country, spring is finally here. But conditions are still a little behind normal, about two weeks in the Eastern half of the U.S., and even further behind in New England, says Jill Calabro, Nufarm plant pathologist.
Out West, however, conditions have been warmer and drier. “So when conditions are dry, generally the pest pressure is a little bit lower in most cases, but everything is warmer so things are sped up a little bit, especially in the Pacific Northwest and California,” Calabro says.
Northern pests
Annual bluegrass weevil. Applications should start in April as these start to lay eggs, says Jeff Marvin, manager of field research for PBI/ Gordon. You can also apply in May to target the pupa of new annual bluegrass weevils. To spot them, look for yellowing patches in bluegrass turf.
Grubs and billbugs. While pressure isn't too bad early in the season, Calabro says, there could be some springtime damage from grubs that were not properly controlled last season. “The recent cold and wet weather has made it hard to get preventative treatments out on time,” she adds.
Grubs are easiest to control with preventative applications in the spring. Curative treatments can be done in the summer, but control is much more difficult, Marvin says.
According to Dean Mosdell, Syngenta technical manager for the Western U.S., grubs of several beetle species in the area can cause significant turf damage in late summer as they feed on roots. Look for dry, brown patches in the lawn and check the soil moisture. If the soil isn't dry, give the lawn a good pull. If it comes up easily, grubs or billbugs are most likely eating away at the root system.
Billbugs are a persistent problem and feed on turf in the early summer, especially on Kentucky bluegrass lawns, Mosdell says.
A good imidacloprid product should solve the problem with an application and a follow-up two weeks later. The lawn will require extra watering after grub damage in order to establish new roots.