First Report of Carrot Beetle ( Tomarus gibbosus ) Damage to Golf Course Turf

In early June 2015, superintendents at Heritage Park Golf Course (HPGC) (Johnson County, Kansas) and Dub’s Dread Golf Club (DDGC) (Wyandotte County, Kansas) reported unfamiliar beetles burrowing into greens and attracting vertebrate predators that caused additional damage. Specimens were brought to Dr. Brett Ratcliffe, University of Nebraska, who identified them as carrot beetles, Tomarus gibbosus (De Geer), a widely distributed North American scarab. This is the first report of direct or indirect damage from T. gibbosus in any turfgrass setting. Adult T. gibbosus were discovered at night/early morning either crawling across greens and collars or partially inserted into the soil (Fig. 1). Adult burrowing left behind circular or D-shaped holes about 8 mm (5/16 inches) in diameter, tufts, and small piles of soil (Fig. 2). Further dissection of burrows yielded beetles just under the surface or, in some cases, 5 to 10 cm (2–4 inches) deep. Beetle activity was initially on and just inside collars but became distributed throughout greens. Burrows and adults were found on all greens of both courses, with more heavily infested ones showing 15 to 20 burrows and beetles per green. The HPGC greens are 70% ‘Pennlinks’ creeping bentgrass (Agrostis stolonifera L.) and 30% annual bluegrass (Poa annua L.) on a high-sand root zone mix conforming to United States Golf Association specifications. The DDGC has pushup greens with native soil and a 50:50 mix of ‘Penncross’ creeping bentgrass/annual bluegrass. Predators, probably skunks (Mephitis mephitis) and raccoons (Procyon lotor), caused additional damage to the greens at HPGC (Fig. 3). Digging coincided with initial beetle activity and continued until late June. Damage ranged from small scooped-out depressions to larger patches (20–35 cm [8–12 inches]). Once vertebrate damage became apparent, lambda-cyhalothrin (Scimitar GC, Syngenta) at 77 g a.i./ ha (0.069 lb a.i./acre) was applied 10 June 2015. Adult beetle activity was suppressed, but vertebrate damage was noted again 9 days after application, so carbaryl (Sevin SL, Bayer) was applied at 4.5 kg a.i./ha (4 lb a.i./acre). The DDGC also Published in Crop Forage Turfgrass Manage. Volume 2. DOI: 10.2134/cftm2015.0188 © 2016 American Society of Agronomy and Crop Science Society of America 5585 Guilford Rd., Madison, WI 53711