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Weevils And Wear Spots May 19, 2017 By Paul Jacobs, agronomist, Northeast Region

Creeping bentgrass (left) has limited growth and recovery potential during cool weather. Limit the amount of wear on creeping bentgrass until warmer weather arrives.

Springtime cultivation, mowing frequency and plant protectant applications all play a role in how well turf will perform a few months from now. Preparing the golf course for summer starts by managing pests and promoting plant health before temperatures heat up.

For golf courses with annual bluegrass playing surfaces, the annual bluegrass weevil (ABW) can be a very problematic pest. Damage caused by the larvae can significantly affect playing conditions. In some areas, ABW have become resistant to insecticides that once provided effective control. For this reason, insecticide applications should be made with resistance management in mind. Factors to consider when making an application for ABW control include:

Historical pressure and damage – If damage from ABW is problematic every year, insecticide applications are warranted and the overall ABW management program should be re-evaluated. Spot treatments are ideal if the same areas are affected each year. If damage is common after insecticide applications have been made, resistance may be an issue.

Scouting – Scouting is essential to determine insect location, quantity and life stage.

Plant health – Improving growing environments and optimizing plant health will help turf tolerate larger populations of ABW.

Insecticide selection – If an insecticide application is necessary, make sure that it is effective against the targeted life stage of the insect. Newer insecticides can provide effective control against ABW, but overuse of any product will encourage the development of resistance in ABW populations. Products that are effective on all stages of insect development are best applied when multiple generations are present. It also is wise to limit usage of new insecticides to once per year and to apply only to affected areas in an effort to avoid resistance.

Annual bluegrass weevils cause concern for many facilities – the number of alerts, articles, emails and blog posts about ABW serve as proof. Keep in mind that these notifications are not a green light for applications. Information about the insect’s life cycle and activity at other courses can be valuable, but should be treated as only one part of an integrated pest management program that is tailored specifically to your course.

It is also important to note that ABW do feed on creeping bentgrass, but mostly after the annual bluegrass populations have been exhausted. Furthermore, creeping bentgrass can tolerate higher quantities of ABW before signs of damage appear.

Courses in the Northeast with creeping bentgrass playing surfaces are facing their own challenges this spring. Cool temperatures have led to slow growth, making creeping bentgrass vulnerable to mechanical injury.

If managing creeping bentgrass, watch for mechanical injury during periods of slow growth and recovery. If creeping bentgrass cannot outgrow wear from golfer and maintenance traffic, the frequency of maintenance practices should be reduced until warmer weather arrives.


Northeast Region Agronomists:

David A. Oatis, regional director –

Adam Moeller, director, Green Section Education –

James E. Skorulski, agronomist –

Elliott Dowling, agronomist –

Addison Barden, agronomist –

Paul Jacobs, agronomist –

Information on the USGA’s Course Consulting Service 

Contact the Green Section Staff

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