You Are Here: Management Updates 2003 Archive August 5, 2003

Date: August 5, 2003
Category: Insects
Subject: Golf Course Grubs

A couple people have asked recently about grubs that looked kind of like black turfgrass ataenius grubs (BTA) but were 0.75 inch or longer. The grubs were described as having no distinct rastral pattern. In each case grubs were reported to be active in the rough area of a golf course, and skunks (or raccoons) were ravaging the area.

Without seeing the specimens, I cannot be sure but one possibility (particularly for those in southeastern Massachusetts) would be northern masked chafers (NMC). These grubs are usually slightly larger than Japanese beetles, and in some areas NMC adults began laying eggs earlier than Japanese beetle females did, so some of them could be nearly an inch long now.

Northern masked chafer grubs have a transverse anal slit. (That just means the slit follows the contour of the tail of the grub, just like the slit on a Japanese beetle.) The hairs in front of the slit are scattered randomly, with no discernable pattern. (In comparison the Japanese beetle has a very distinct V-shaped row of spines in front of the slit.)

Black turfgrass ataenius grubs are never more than a half inch long. The most distinguishing feature of the rastral pattern is that they have two pad-like structures just in front of the anal slit.

If skunks or raccoons are tearing up the affected turf (as has been the case with at least one of these reports), NMC grubs normally are controlled fairly easily with an application of Dylox™ (trichlorfon). As always, remember to water it in!

- Submitted by: Dr. Pat Vittum