Impact of Soil Moisture and Mowing Height on Ataenius spretulus (Coleoptera: Scarabaeidae) Selection of Golf Course Turf Habitat in Choice Tests

Abstract

Ataenius spretulus (Haldeman) (Coleoptera: Scarabaeidae) is the most common grub in golf course fairways in Michigan. Ataenius spretulus grubs are 3- to 10-fold more abundant in golf course fairways (mowed at a height of 1.5 cm) than in the roughs (mowed at a height of 5.0 cm or higher). Predation and infection by Paenibacillus sp. were previously reported to be greater in the rough, and may partially explain outbreaks of A. spretulus grubs in golf course fairways. In addition to natural enemies, cultural practices of irrigation and mowing could also be important factors, especially if A. spretulus prefers to oviposit in the fairway over the rough. In this paper we examine the impact of soil moisture and mowing height on oviposition and habitat selection. In a greenhouse experiment where A. spretulus adults were given a choice of turf maintained at fairway or rough height, no ovipositional preference for one or the other was observed. In three different growth chamber experiments where adults were allowed to choose among fairway or rough turf plugs held in soil at different moisture levels, adults preferred turf plugs in soil at a volumetric moisture content of 13% to 26% over turf plugs in soil at 8% to 9% moisture for their habitat selection. We conclude from these greenhouse and growth chamber experiments that A. spretulus adults do not choose turf habitat based on mowing height, but may be influenced by soil moisture levels.