You Are Here: Management Updates 2006 Archive September 15, 2006

Date: September 15, 2006
Category: Insects
Subject: White Grubs, Annual Bluegrass (Hyperodes) Weevil, Sod Webworm

White grubs are active now throughout the Northeast. Most are second or third instars now, and it is becoming increasingly difficult to manage them. Trichlorfon (Dylox™) is probably the best bet for those who have access to it. (Reminder that Dylox™ is not allowed on school grounds in Masschusetts and is not available in Maine. There are, no doubt, other restrictions of which I am not aware.) Most other products will not work quickly enough now.

If you do apply Dylox™, be sure to water it in with at least 0.1 inch of water. (More irrigation is even better.) And be sure to check the pH of the water you are using in the tank. If the pH is above 7.5, Dylox has a tendency to break down quite quickly in the tank, so use an additive that will lower the pH to 7.0 or less. (Many people ask what to do if the irrigation water pH is high. Studies in Alabama showed that it is more important to irrigate, even if the pH is high, than to leave the material unwatered.)

Annual bluegrass weevils. Believe it or not, I have had three phone calls in the last two days from golf course superintendents reporting that annual bluegrass weevil (ABW) larvae are active in tees, collars, or fairways. In most cases, I would not recommend trying to manage these larvae with insecticides. We are past the agronomic stresses of summer, and the turfgrass is recovering nicely, so it should be able to outgrow any damage the larvae might inflict. And most larvae should be pupating very soon, so they are very nearly done feeding anyway. Make a note in your records of where you are seeing the activity, so you can concentrate controls on those locations next spring.

Sod webworms have been active in many parts of New England. There are several species that can occur here, but the bluegrass sod webworm and vagabond sod webworm are the most likely suspects at this time of year. Again the turf is growing very well in most locations, so control normally is not necessary.

Submitted by: Dr. Pat Vittum

DISCLAIMER - As always, it is the responsibility of the applicator to verify the registration status of any pesticide BEFORE applying it. Different states have different regulations as well. The author and the University of Massachusetts are not liable for any consequences of any pesticide "recommendations". Mention of any trade name is not to be considered endorsement of a product.

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