Golfdom, June 2011

ABW vacuum sampling proved as reliable and consistent as soil coring www turfgrasstrends com June 2011 TurfGrass Trends 39 then determine if there is a correlation between adult densities and future larval densities Fairways on three golf courses in central and northern New Jersey were sampled weekly by vacuum and core sampling from late March through the end of the third generation in mid October to estimate adult abundance and to compare techniques A leaf blower vacuum was fit with a mesh 324 openings per square inch basket to capture adults as they entered the nozzle A section of fairway 36 square feet was vacuumed by placing the nozzle directly on the turf and vacuuming in a zig zag pattern while maintaining a tight fit of nozzle and turf The entire section was covered during 10 seconds of vacuuming Afterward the basket was emptied on a tray and the numbers of adults counted The estimate of adults in vacuum samples was compared to destructive soil sampling with a turf plugger followed by saline extraction in the laboratory The relationship between the number of adults vacuumed and future larval densities was studied on the edges of six fairways On each fairway 32 plots each 36 square feet were sampled to estimate adult density Each plot was vacuumed weekly between the start of adult emergence from overwintering sites through the end of the egg laying period of the overwintered adults mid May in northern New Jersey Once the egg laying period was complete the plots were sampled for larvae and larval densities were compared to the numbers of adults captured in weekly sampling periods as well as during the entire adult sampling period results ABW vacuum sampling proved as reliable and consistent as soil coring saline extraction for estimating adult densities and peaks in abundance But vacuum sampling was non damaging to the turf took less time to process a sample and gave instantaneous information on presence and density Additionally vacuum sampling detected adults in low densities on fairways prior to when plant indicators Forsythia full bloom would have indicated in both years of the study In each year of the study vacuuming sampling allowed us to detect two separate peaks in adult densities indicating staggered emergence from overwintering sites The timing of the two peaks was similar between courses and years 1st April 21 23 2nd May 5 7 Strong relationships were found between number of adults collected in vacuum samples and future larval densities in both years The number of adults collected either during the second peak of adult abundance or across the entire 6 week sampling period was significantly correlated with larval densities These correlations suggest that egg laying occurs over an extended period yet the majority of eggs are deposited during the second peak in abundance Future work is needed to optimize the size of the area sampled and the number of samples needed to adequately correlate adult and larval densities to best integrate curative controls Conclusions Turfgrass managers have several methodologies to assess ABW populations Unfortunately most turf managers opt to manage ABW without assessing presence or population density Our studies indicate that vacuum sampling can be an effective tool and provide a rapid estimate of ABW adult density In addition we found that adult counts on fairways are correlated to future larval densities Future work is needed to determine adult ABW density thresholds and if this information can aid in targeting curative controls against larval stages dr Benjamin McGraw is an assistant professor in the department of Golf and Plant sciences at the state University of new York sUnY at delhi dr Albrecht Koppenhöfer is a professor and turfgrass extension specialist in the department of entomology at rutgers University in new Brunswick n J REFERENCES diaz M d and d C Peck 2007 Overwintering of annual bluegrass weevils Listronotus maculicollis dietz Coleoptera Curculionidae in the golf course landscape entomologia experimentalis et Applicata 125 259 268 McGraw B A and A M Koppenhöfer 2009 development of Binomial sequential sampling Plans for Forecasting Listronotus maculicollis Coleoptera Curculionidae Larvae Based on the relationship to Adult Counts and Turfgrass damage Journal of economic entomology 102 3 1325 1335 Tashiro H C L Murdoch r W straub and P J Vittum 1978 evaluation of insecticides on Hyperodes sp a pest of annual bluegrass turf Journal of economic entomology 70 729 733 PHOTO COURTESY BEnjamin a mCGRaw Ad Index Advertiser Page The Andersons 4 27 B A S F Corp 16 17 22 Bayer Environmental CV2 1 Becker Underwood 26 Buffalo Turbine 24 Champion Turf Farms 5 Duro Tire 29 Ecologel 28 FMC Professional 10 11 Gro Power 30 Horizon CV3 Kochek 32 Lebanon Turf CV4 Malt Products 30 PBI Gordon 3 13A Seago 28 Sonic Solutions 31 Specialized Turf Equip 34 Syngenta 7 TifSport Insert reg White Metal Golf 32 Wireless Solutions 31 This index is provided as an 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