Golfdom, December 2011

I M P A C T O F E P N O N A B W FIGURE 1 EPN IMPACT ON ABW DENSITIES Effect of EPN species strain and application rate on ABW densities Numbers above or within columns indicate percent reduction relative to the density in the untreated control Letters above columns 2008 indicate significant differences Tukeys pairwise comparison test P 005 between EPN species when all rates were combined Continued from page 33 in most instances control was more variable 0 71 percent than in 2006 and likely attributable to higher ABW densities Between the two application rates Sc provided the most consistent control 64 69 percent In 2008 the previous top performing species Sf Sc and Hb were tested at three application rates 2 1 and 05 billion IJs per acre to intermediate ABW densities 35 40 ABW ft2 Sc provided the highest and most consistent control 60 83 percent however without clear dose effect and not significantly better than Sf Conclusions Our findings in laboratory bioassays and evidenced in select field trials suggest that ABW larvae are very susceptible to several commercially available EPNs and that curative control of ABW with EPNs may be feasible Our results indicate that Sc and Sf could provide control comparable to chemical insecticides 80 percent when applied at standard rates 1 billion IJs per acre to moderate larval densities Although each species demonstrated the capability of high control in the field the range of control Sf 10 94 percent Sc 60 83 percent is currently far too variable for reliable use on valuable turf Additionally we observed a significant decrease in susceptibility between fourth and fifth instar ABW larvae in laboratory bioassays which may indicate that the application of nematodes must be precisely timed to achieve high levels of control Future studies will investigate the role that pest density and application timing have on control levels to reduce the variability in control Dr Ben McGraw is an assistant professor in the Department of Golf and Plant Sciences at the State University of New York SUNY at Delhi NY Dr Albrecht Koppenhöfer is a professor and turfgrass extension specialist in the Department of Entomology at Rutgers University in New Brunswick NJ Reach McGraw at mcgrawba@ delhi edu REFERENCES McGraw B A and A M Koppenhöfer 2007 Biology and Management of the Annual Bluegrass Weevil Listronotus maculicollis Coleoptera Curculionidae in Handbook of Turfgrass Physiology and Management M Pessarakli ed Taylor and Francis Boca Raton FL pp 335 350 McGraw B A and A M Koppenhöfer 2009 Population dynamics and interactions between endemic entomopathogenic nematodes and annual bluegrass weevil populations in golf course turfgrass Applied Soil Ecology 41 77 89 Ramoutar D S R Alm and R S Cowles 2009 Pyrethroid resistance in populations of Listronotus maculicollis Coleoptera Curculionidae from southern New England golf courses J Econ Entomol 102 388 392 This article was based on two published papers McGraw B A and A M Koppenhöfer 2008 Evaluation of two endemic and five commercial entomopathogenic nematode species Rhabditida Heterorhabditidae and Steinernematidae against annual bluegrass weevil Coleoptera Curculionidae larvae and adults Biological Control 46 467 475 McGraw B A P J Vittum R S Cowles and A M Koppenhöfer 2010 Field Evaluation of Entomopathogenic Nematodes for the Biological Control of the Annual Bluegrass Weevil Listronotus maculicollis Coleoptera Curculionidae in Golf Course Turfgrass Biocontrol Science and Technology 20 2 149 163 Ad Index Advertiser Page The Andersons 2 17 B A S F Corp BB CV2 9 Becker Underwood 3 Jacobsen 7 John Deere CV3 Kochek 27 Lebanon Turf CV4 NE Regional Turfgrass 35 PBI Gordon 27 Petro Canada 5 Richway Industries 16 Standard Golf 26 Turfco Mfg 11 Wireless Solutions 13 This index is provided as an additional service The publisher does not assume any liability for errors or omissions 34 TURFGRASS TRENDS December 2011 www turfgrasstrends com