Impact of Golf Course Mowing Practices onAtaenius spretulus(Coleoptera: Scarabaeidae) and its Natural Enemies

Abstract

In April of 1996 the rough-fairway interface of a golf course consisting entirely of perennial ryegrass, Lolium perenne L., was altered by implementing a new mowing regime. The experiment contained 4 replications of 4 treatments: turf mowed to fairway height 1995-1997, turf mowed to rough height 1995-1997, turf that was fairway height in 1995 and was allowed to grow to rough height in 1996-1997, and turf that was rough height in 1995 and was cut to fairway height in 1996-1997. Glass vials were used as pitfall traps to monitor activity of surface-dwelling predators and adult Ataenius spretulus (Haldeman). In 1996, the most A. spretulus larvae were found in plots where the turf was mowed to fairway height the previous year, regardless of how the turf was mowed that year. However, adult Philonthus spp. (Staphylinidae) were found in the highest numbers in the plots that were mowed to rough height, regardless of the turf height in past years. In 1997, the highest populations of A. spretulus adults and larvae were found in plots mowed to fairway height in 1996 and in 1997, regardless of 1995 mowing height. Also, twice as many larvae were infected with a milky disease causing pathogen, Bacillus sp., in the rough (68%) compared with the fairway (34%). The most prevalent staphylinids, Philonthus cognatus Stephens and P. carbonarius (Gravenhorst), were 3 times more abundant in rough-mowed turf compared with fairway-mowed turf. With grass species, irrigation, and previous pesticide use controlled by our experimental design, it appears that mowing practices are an important factor contributing to the skewed distribution of A. spretulus toward golf course fairways and away from the rough.