The Annual Bluegrass Weevil is an insect that causes damage to, you guessed it, Poa Annua! This tiny insect can cause serious damage to our predominately Poa Annua golf course. We normally go through several generations in a season. We begin our control strategy in early spring by targeting adults before they lay their eggs. Next we target young larvae that have hatched. The larval stage is the damaging stage. The larvae chew on stems and crowns of the plant. The damage actually looks like wilt during periods of high heat stress. If you don't notice it until then you are too late. The damage has been done. A key component to the program is early season timing. If we can reduce early populations, subsequent populations will be reduced.
Less adults = less eggs = less larvae
Kill larvae = less adults = less eggs = less larvae
See the pattern?
The pest control theory is to continually reduce the populations throughout the season. By the time we hit the third generation we hope the population is so small that control is not necessary or at least "spot treating" will suffice.
The difficulty with control is that life cycle timing of ABW's varies from year to year and generations will commonly overlap.
We use indicator plants and regimented scouting to determine insecticide application timing. It doesn't hurt that we've been doing this for many years. We are well aware of where our "hot spots" are and scouting is done more frequently in these areas.
One last issue with control of ABW's is that many courses, especially in Connecticut, are finding that the insects are becoming resistant to certain pesticides. This reduces the ability to attack the pest at different stages in their life cycle. Luckily, we have not seen this problem yet.
To learn more about the Annual Bluegrass Weevil, check out the following link which will connect you to an excellent Cornell University fact sheet...
The following pictures were taken this morning...
|ABW Pupae (stage before adult) 7-23-10|
|ABW Adult 7-23-10|
What does this mean to us?
We are doing just fine this season!