One of the most frequently used fungicides on golf courses, chlorothalonil, was applied to field plots at four different golf courses to determine how Ataenius spretulus Haldeman, Aphodius granarius L., carabids, staphylinids, formicids and Paenibacillus sp. were affected. Chlorothalonil had no influence on the incidence of Paenibacillus sp. infection of A. spretulus larvae in golf course fairways. The incidence of Paenibacillus sp. infection of A. spretulus larvae was much greater in the rough (47.4%) compared with the fairway (26.4%) at Cattails Golf Club despite a more dense population (fourfold) of larvae in the fairway. Chlorothalonil treatment of turf plots had no influence on the number of staphylinids, carabids, formicids, or A. spretulus adults caught in pitfall traps. It also did not affect the density of A. spretulus larvae. Data from this study suggest that the widespread use of chlorothalonil on fairways is not likely to cause outbreaks of A. spretulus on golf courses.