White Grubs On Greens October 24, 2013 By Todd Lowe

White grubs feed on turfgrass regionalUpdateContents and create small distinct patterns of damage on greens. A cup cutter was used to reveal the culprit.

The warm, subtropical climate of South Florida supports the growth of many turfgrass pests. Mole crickets and nematodes are, by far, among the most damaging pests on Florida golf courses, but occasionally we see other “critters” on our visits. 

While on a visit to a golf facility this past week, small semi-circular to crescent-shaped brown spots were observed on several putting greens. These scuff marks were two to three inches long and if there weren’t multiple spots in each location they might have gone unnoticed. A soap flush was unsuccessful at bringing anything to the surface so a cup cutter was used to pinpoint the cause of the problem: a white grub. 

There are a number of types of beetles that lay their eggs in turf at different times of the year. These eggs hatch and their larvae (grubs) feed on turfgrass regionalUpdateContents. Oftentimes, these pests go unnoticed but can create a drought-like appearance if their populations become large enough. Additional damage can be caused by predators like birds, skunks and armadillos that dig for white grubs, one of their favorite food sources. 

Unfortunately, we killed the pest before a more in-depth diagnosis of its raster pattern and anal slit (yes, we actually identify grubs by looking at their rear ends) was made. However, this particular grub was most likely from a green June beetle or a sugarcane beetle, as they are more active later in the year. To learn more about the life cycles and control of white grubs in Florida, see the article White Grub Management in Turf from University of Florida entomologist, Dr. Eileen Buss.

Source:  Todd Lowe (

Information on the USGA’s Turf Advisory Service

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