You Are Here: Management Updates 2009 Archive May 1, 2009

Date: May 1, 2009
Category: Insects
Subject: Annual Bluegrass (Hyperodes) Weevil

With the warm weather that most of the region experienced earlier this week, the flowering trees and shrubs have been developing incredibly quickly. Many sites throughout central New England progressed from Forsythia "full bloom" to "half green - half gold" in less than a week.

Now is the time to be applying pyrethroids if you are targeting ABW adults in central New England. Do not delay much longer if the Forsythia have been showing green for even a few days in your area. For those of you further north, where Forsythia are still at full bloom, keep in mind that many years we have found that applications of pyrethroids made at Forsythia full bloom have not performed as well as those made slightly later in the spring. We assume this is because some adults are a little slow getting underway in the spring (aren't we all???) and the early applications don't reach them. (Note that many superintendents in the metropolitan New York area have had good success using a pyrethroid at full bloom but our experience suggests that it often pays to hold off just a little).

If you are planning to use Acelepryn™ against ABW this year, the "half green - half gold" timing seems to be ideal. This application is made at the traditional time for targeting adults but in fact will be effective against the young larvae just as they emerge from the eggs. So you need to give the product time to get into the vascular system of the plant. Provaunt™ , the other new DuPont product, should be applied when medium-sized larvae begin to emerge from the stems of the plants. That may be as soon as two or three weeks after "half green - half gold", and it could be as long as four or five weeks after "half green - half gold", depending on the temperatures over the next month. Meanwhile any of you who are using one of the combination products (Allectus™ or Aloft™ ), now (assuming you are at full bloom to "half green - half gold") would be an excellent time to make the application. Refer to the DuPont "Weevil Track" website (http://www.weeviltrak.com ) to see how the ABWs are developing up and down the eastern seaboard. The website is providing excellent information on the stage of development of Forsythia and the first emergence of weevil adults and larvae. (Larvae are already active in Maryland ... and we'll see them here soon enough!)

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.

Links followed by the symbol are external links that open in a new window.