Golf Course Management

JAN 2019

Golf Course Management magazine is dedicated to advancing the golf course superintendent profession and helping GCSAA members achieve career success.

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112 GOLF COURSE MANAGEMENT 01.19 Active ingredient Insecticide class Trade name Target Rate pounds a.i./acre [grams a.i./hectare] Bifenthrin pyrethroid Talstar adult 0.100 [112] Chlorpyrifos organophosphate Dursban adult 1.000 [1121] Trichlorfon organophosphate Dylox lm 6.000 [6725] Spinosad spinosyn Conserve lm 0.400 [448] Indoxacarb oxadiazine Provaunt lm 0.225 [252] Chlorantraniliprole anthranilic diamide Acelepryn ls, lm 0.156 [175] Cyantraniliprole anthranilic diamide Ference ls, lm 0.156 [175] Clothianidin neonicotinoid Arena ls, lm 0.247 [277] Abbreviations: ls, small larvae; lm, medium-size larvae. Table 2. Active ingredients and product names of insecticides tested against ABW. Insecticides tested against annual bluegrass weevil course staff following the same standard pro- cedures as for the rest of the fairways but were not treated with insecticides until after experi - mental evaluation. Treatment timing was determined using a combination of indicator plant phenol - ogy, growing degree day accumulation (base temperature 50 F [10 C], starting March 1; GDD 50 ) and ABW phenology. Bloom of three indicator plants (forsythia, Forsythia spe - cies; flowering dogwood, Cornus florida; hy- brid Catawba rhododendron, Rhododendron catawbiense) was observed in regular visits. GDD 50 accumulations were calculated based on data obtained from the nearest weather sta - tion for each golf course. Adult densities were estimated weekly by taking four 10-second vacuum samples from the start of full bloom of forsythia until past the peak of adult den - sities. Larval populations were monitored weekly from late-bloom dogwood through late-bloom rhododendron by taking 30 soil- sod cores (including grass, thatch and the soil below it to a total depth of 1.5 inches) and ex - tracting ABW stages (see below). Applications were made with a CO 2 backpack sprayer with a flat-fan nozzle at 30 pounds/square inch (207 kPa) pressure in 2 gallons/acre (823 liters/hectare) spray volume. Treatments were immediately watered-in with overhead irrigation. Untreated control plots received only overhead irrigation. Treatments were arranged in a randomized complete block design and replicated six times per trial. Insecticides targeting adults and larvae were evaluated in different experiments that were arranged immediately adjacent to each other. Treatments were evaluated around 700 GDD 50 (early June) when most individuals of the ABW spring generation were in the fourth to fifth instar. From each replicate, eight cores (2.25 inches [5.7 cm] diameter × 1.5 inch [4 cm] depth) were taken, and ABW stages were extracted by submerging the cores (split in four pieces) for one hour in lukewarm satu - rated table salt solution. Data were the com- bined number of larvae (all stages), pupae and teneral (not fully sclerotized) adults per rep - licate. Mature adults were not included be- cause, at this time, they were likely to origi- nate from the overwintering generation and might have migrated into the replicates from adjacent areas after residual effects of treat - ments had subsided. Highly susceptible to pyrethroids Tolerant of/resistant to pyrethroids HF North Brunswick, N.J. EW River Vale, N.J. HP Howell, N.J. GB Somers Point, N.J. PB Manalapan, N.J. LI Glen Cove, N.Y Table 1. Field testing sites where annual bluegrass weevils are either highly susceptible to or tolerant of or resistant to pyrethroids. Sites where ABW are susceptible to or tolerant of or resistant to pyrethroids ceptible (RR 50 2: PB, Manalapan, N.J.; HP, Howell, N.J.), moderately resistant (RR 50 31: GB, Somers Point, N.J.), resistant (RR 50 95: EW, River Vale, N.J.) and highly resistant (RR 50 343: LI, Glen Cove, N.Y.) (Table 1). Field experiments Field experiments targeting overwintered adults and young and midsize larvae of the spring generation were conducted at four golf courses in 2015 (HP, GB, EW, LI) and five golf courses in 2016 (PB, HP, GB, EW, LI) in fairway areas with a history of ABW problems (Table 1). In all experimental areas, the grass was a mixture of about 20%-50% Poa annua and 50%-80% creeping bentgrass (Agrostis stolonifera) and was mowed at 0.5 inch (13 mm). Plot areas were managed by the golf

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