Coming soon to the Northeast… Annual Bluegrass Weevil
Annual bluegrass weevil (previously known as Hyperodes weevil) will be a primary focus of golf course superintendents in the northeastern United States who manage annual bluegrass turf. The annual bluegrass weevil (Listronotus maculicolis) has been reported in New England, New York, New Jersey, Maryland, Delaware, Virginia, North Carolina, West Virginia, Pennsylvania and eastern Ohio. The annual bluegrass weevil overwinters as an adult under leaf litter around bushes and trees often in the rough areas. In early spring, usually in April, the adult weevils will move from the rough areas on to annual bluegrass fairways and greens.
Figure 1: Annual bluegrass weevil damage on a putting green.
As annual bluegrass weevils move across the fairways and greens, the females will chew a small hole at the base of the stem to deposit, on average two eggs. The eggs hatch producing larvae that chew their way further into the stem. Moving from stem to stem, the larvae hollow out the stems as they chew down through the crown. Often sawdust like material called frass is left behind. This frass is a sign of this pest.
Figure 2. Annual bluegrass weevil adults
The degree of damage caused by these larvae is dependent on the infestation level. Light infestations cause a slight yellowing and browning of the turf. Moderate infestations cause small irregular patches of dead turf and heavy attack kills turf in large areas. Damage begins to become obvious in late May or early June and is often mistaken for disease or environmental problems. Hollowed out grass stems and leaf notching are diagnostic characters.
Cultural controls in general are not very effective for annual bluegrass weevil control. Removing leaf litter from roughs especially needles under white pines, and other conifers is one practice. Chemical control through the use of insecticides can be variable with preventative treatments more effective than curative treatments.
Suggested application during spring: When the adult weevils are observed walking across the fairway or green, which may correspond with dogwood (Cornus florida L.) bloom (April), a preventative application should be made.
For more specific information on both the insect and control programs see WeevilTrak.com
About the author
Dr. Karl Danneberger is a professor of Turfgrass Science at The Ohio State University. Dr. Danneberger's contact information can be found here. You may also follow Dr. Danneberger on Twitter: