Black turfgrass ataenius and other white grubs are sporadic pests on Midwestern golf courses. Milky disease (Bacillus popilliae) is known to be a natural enemy of this pest, but the impact of other natural enemies, such as generalist predators, had not been studied.
Five golf courses in Michigan that were not treated with insecticides were sampled with pitfall traps. Potential predators captured included rove beetles, ants, ground beetles and histerid beetles. The number of predators declined sharply from the rough into fairway, even though both areas were composed of the same grass species and received similar irrigation. Black turfgrass ataenius larvae were much more abundant in the fairways than in the rough. This was not entirely explained by a female oviposition preference for fairways. The lower populations in the rough may be due to predation by the larger number of predators there.
The biggest difference between fairway and rough was mowing height and fertilization. The short-grass fairway may not be as suitable of a habitat as the longer grass of the rough for the predators, but there also may be less prey available in the fairways to support predator populations. There was no way to determine if disturbance and compaction from frequent mowing affected predator abundance. In previous studies, rove beetles and spiders were found to be more abundant in low maintenance home lawns than in those that were mowed frequently. Increasing mowing height may help encourage naturally-occuring predators that impact black turfgrass ataenius populations.
Smitley, D. R., T. W. Davis, and N. K. Rothwell. 1998. Spatial distribution of Ataenius spretulus, Aphodius granarius (Coleoptera: Scarabaeidae), and predaceous insects across golf course fairways and roughs. Environ. Entomol. 27(6): 1336-1349.
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