Opening Season Against Number One
A dishearting aspect of any upcoming college football season is to find out that your favorite team is playing in the season opener the number one ranked team in the country. It is tough way to start the season and often casts a shadow throughout the season. Annual bluegrass weevil is much like playing the number one ranked team at the beginning of the season. For golf courses primarily the northeast but extending through the mid-Atlantic region and west to Ohio annual bluegrass weevil is a major pest problem that starts early in the season and if not adequately controlled stretch through the summer. To control the pest requires proper timing and multiple insecticide applictions.
The annual bluegrass weevil (Listronotus masulicolis) 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 and pupae.
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.
One successfull program for controlling annual bluegrass weevil through the season is the Annual Bluegrass Optimum Control Strategy found on this website as part 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: