Golf Course Management

MAR 2017

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

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74 GOLF COURSE MANAGEMENT 03.17 be explained by the significantly greater fre- quency of annual bluegrass weevil applications (5.8 vs. 3.5 per year) (n = 261; U = 2666; P < 0.001). More than 40% of "resistant" courses but only 10% of susceptible courses reported making more than five applications per year. Additionally, 18% of "resistant" courses re - ported making 10 or more applications to control annual bluegrass weevil. Chemical selection differed greatly be - tween the two types of annual bluegrass weevil populations (Figure 3). Larvicides, especially chlorantraniliprole, indoxacarb (Provaunt, Syngenta), spinosad (Conserve, Dow AgroSciences) and trichlorfon (Bayer, Dylox) tended to be used more on courses with "resistant" annual bluegrass weevil than on courses with susceptible populations. Most superintendents of courses with "resistant" populations (93%) used chlorpyrifos (Dow AgroSciences, Dursban) for adult manage - ment. However, a relatively high percentage of respondents (64%) still used pyrethroids. The number of annual pyrethroid applications on golf courses with "resistant" annual blue - grass weevil populations was not significantly different from the number with susceptible populations (n = 256; U = 4668.5; P = 0.30). Courses with "resistant" populations were also much more likely than courses with suscepti - ble populations to select older broad-spectrum insecticides such as trichlorfon (Bayer, Dylox) (67% vs. 34% for susceptible courses) or car - baryl (Bayer, Sevin) (21 % vs. 11%). Integrated pest management Pest control decisions for golf courses are based on aesthetics, playability and avoid - ance of damage, hence strong emphasis is placed on preventive chemical control of in - sects, diseases and weeds. Turfgrass managers nevertheless can incorporate many aspects of integrated pest management (IPM) into their management of annual bluegrass weevil. Most respondents (73%) indicated that they "al - ways" or "sometimes" employ spot-treating as a means of controlling annual bluegrass weevil. Only 16% indicated that they never spot-treat. A greater than average number of responses from the Delaware-Maryland-Vir - ginia region (40%) indicated that those su- perintendents "never" employ spot treatments. This is surprising given the relatively short history of damaging populations in the region and the lower amounts of P. annua present on those golf courses. 0 10 20 30 40 50 60 70 80 90 100 Susceptible "Resistant" Percentage of responses Pyrethroids Chlorpyrifos Carbaryl Anthranilic diamides Indoxacarb Trichlorfon Spinosad Neonicotinoids Combination products Adulticides Larvicides Figure 3. Chemical insecticides used in Listronotus maculicollis (annual bluegrass weevil) management, and comparison between pyrethroid-susceptible and "resistant" courses. Combination products include insecticides with two active ingredients (for example, bifenthrin + imidacloprid). Insecticide use on susceptible and 'resistant' courses

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