P&PDL Picture of the Week for
September 27, 2010

Late Season Insects Found in Turfgrass

Doug Richmond and Tim Gibb, Turfgrass Entomologists, Purdue University

The following letter and pictures were sent to us for identification. There was a buzz of follow-up letters and communication afterward indicating that maybe this is not just an isolated occurrence.  I have enclosed the initial letter, accompanying photographs and the return response in hopes that this is of value to others noticing the same thing:

"Within the past week I have come across 3 separate lawns with grub/billbug type damage, but have found the insect in the attached images.  it resembles a billbug only longer in length.  Can you ID this insect please?

The only similar larvae I have found in the reference material we have on site is a dichondra flea beetle, but that material also only shows them as a problem in CA."

The insect in the pictures appears to be the cranberry girdler Chrysoteuchia topiaria which is also an occasional pest of turfgrass.  It is a member of the sod webworm complex with the main difference in biology being that these larvae tend to feed mainly on the crowns and roots of turfgrass plants.  As a result, the damage very much resembles that of white grubs or billbugs.  Almost any insecticide labeled for caterpillar control in turfgrass will do the job, but unlike with other caterpillars, the insecticide should be watered in after application.

Click image to enlarge

Cranberry girdler

Cranberry girdler

Purdue Plant & Pest Diagnostic Lab Purdue Cooperative Extension Service