7/2/2013 - By Harrell's

By Laurence Mudge, Technical Service Coordinator, Bayer Environmental Science

The annual bluegrass (hyperodes) weevil (ABW) is a major pest of turfgrass in the northeastern United States. However some new ways of thinking about how to more effectively control this pest are emerging.

Some new ways of thinking about Annual Bluegrass Weevils and management

• Traditionally, control of ABW has focused on control of the first generation larvae.
• ABWs walk out of the woods in the spring and fly into the woods to overwinter, but probably overwinter much deeper in the woods than we previously thought.
• ABWs emerge from the woods after winter earlier than we thought.
• Emergence from winter is extended over a longer period of time than we thought.
• We need to trap ABWs to discover first emergence after winter to better determine insecticide application timing.
• ABW adults have to eat while they are migrating into turf areas.
• Adults eat before they lay eggs.
• When you first see ABWs in your traps, wait 7-10 days, and then make an application of Allectus™ GCSC to the rough and 20 feet into the fairway.
  • This approach is targeting the adults and not the larvae.
• This first application will probably be in early April (early spring for most of us).
  • This is two to three weeks earlier than what is historically the timing.
  • Use daffodil at full bloom as an environmental indicator.
• Three to four weeks later come back with your second application of Allectus GCSC
• Allectus GCSC will control the early emerging adults, while getting extended control later emerging adults and larvae.

So is there a new way to think about maximizing control of this destructive insect in turf?

YES, recent research suggests that the best way to control this damaging insect is to employ traps on your course and apply a combination product, like Allectus GCSC, earlier than traditional timings aimed at overwintering adults. The strategy is to apply a combination product to impact the oviposition potential of overwintering ABW adults. Overwintering adults travel from overwintering sites to short cut grass to lay eggs.

The idea is to treat these areas with a product like Allectus GCSC to control these adults and to provide residual control. There is evidence that control of these adults with Allectus GCSC is better than with a synthetic pyrethroid applied alone. To determine the time to make the first application will require simple traps on your course to trap these overwintering adults. Traps need to be in place by mid to late March as overwintering adults start to move out of their overwintering sites sometime by late March to early April.

TOTAL EIGHT ABW control program

• Install ABW traps on your course on the edges of roughs. Install as many as you can manage. Have traps in place by mid to late March. Empty traps every 3-4 days through the summer.
• EIGHT Pints of Allectus GCSC will be applied as a split application.
• Apply 4 pints of Allectus GCSC per acre, 7-10 days after the first ABW adult is found in a trap.
  • This timing is a little earlier than the traditional timing for pyrethroids. For this timing, forsythia may be showing yellow flower buds-first blooms, or full bloom of daffodil.
  • Treat the roughs, and 20 feet into the fairways, plus tees and green complexes.
  • This provides excellent control of overwintering adults and also provides residual control of any larvae that hatches from eggs (first generation).
• Repeat this application 28 days later in the same areas.
  • This second application, in addition to the first application, will provide preventative white grub control for the rest of the season. (If grub control is desired in other areas, make an application of Allectus GCSC or Merit at the normal timing for grub control.
  • This application will control any late emerging adults or second generation of ABW.
• With this TOTAL EIGHT ABW control program, you will also get great control of billbugs, black turfgrass ataenius, and surface feeders such as cutworms, in addition to the control of ABW and white grubs.

Additional Resources

• Concord Country Club Grounds Management Department
• How to Build a Richmond Linear ABGW Pitfall Trap (PDF)