P&PDL Picture of the Week for
September 20, 2004

Grub Damage Becoming Apparent

Tim Gibb, Insect Diagnostician, Department of Entomology, Purdue University

White grub damage on turfgrass may be more widespread than many expected this year.  With ample rain and favorable growing conditions for most host plants during the early and mid growing season, high concentrations of adult Japanese beetles were not as common as in previous years.  This may have lulled homeowners into forgetting about the beetle or assuming that the populations were too low to worry about. Such was not the case, however, and the grub damage reports that are beginning to flood our office, validate that fact. 

Some of the damage caused by grubs is still reversible if the grubs are treated ASAP and the turfgrass is pampered with irrigation and fertilizer during these last few weeks of fall growth.  Dylox is still the best product to apply at this late date for grub control. Most other chemicals do not work well on large grubs.  Be sure to water it in thoroughly if possible. Take advantage of any fall rains that the hurricanes might spawn in our area in the next few days.  Also, keep in mind that Dylox sometimes requires 7-10 days to kill the grubs after application so don’t be in too big of a hurry to apply a second application thinking the first didn’t work.

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Purdue Plant & Pest Diagnostic Lab Purdue Cooperative Extension Service