Golf Course Management

JUL 2014

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

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07.14 GOLF COURSE MANAGEMENT 85 Increasing exposure time to Multiguard Protect effective against ectoparasites like sting nema- todes than it is against endoparasites like lance nematodes. Multiguard is not unique in this respect. Other than Nemacur (which will not be permitted for use on golf courses as of Oct. 6, 2014), none of the turfgrass nematicides currently on the market has systemic activity. However, even endoparasites will spend time in the soil when they can be affected by con - tact nematicides like Multiguard. Like most pesticides, the higher the con - centration of furfural in soil solution, the bet- ter it works (2) (Figure 1). Unfortunately, as rates get higher, the risk of phytotoxicity to turf also increases. The current maximum la - beled rate of 8 gallons/acre (74.83 liters/hect- are) is on the low side with regard to effcacy, but has less potential for negative effects on turf than higher rates. This means that single applications of Multiguard are typically insuf - fcient and, in most cases, several applications are required to reduce nematode numbers in soil and improve turf health. In our feld trials, we usually do not start observing results until after the second or third application. A single application will kill some, but not most, of the nematodes present. Based on our research re - sults, a sequence of applications made at two- to three-week intervals will maximize effects on nematodes while minimizing the poten - tial for phytotoxicity. Application intervals of greater than four weeks are usually too long and allow nematode populations time to re - cover between applications. Maximum effects to nematodes are real - ized after 18 to 24 hours of exposure to Multi- guard (2) (Figure 2). Therefore, after an initial post-application irrigation with ΒΌ-inch (0.635 centimeter) of water, we recommend not irri - gating again until 24 hours have passed. This will allow maximum exposure of the nema - todes to the furfural in soil solution. We also do not recommend applying Multiguard Pro - tect if there is a high risk of substantial rainfall in the 24-hour forecast. We have conducted numerous feld trials with Multiguard Protect on nematode-in - fested bermudagrass (Cynodon species) greens. In most of these trials, we have observed turf improvement after two or three applications (1) (Figure 3). This improvement was great - est from spring and fall applications and not from summer applications. Therefore, for best results in Florida, we recommend applying Figure 2. Effects of increasing exposure time to Multiguard Protect (at 1,500 parts per million in soil solution) on the number of healthy sting nematodes in a laboratory experiment. Increasing concentration of Multiguard Protect Figure 1. Effects of increasing concentration of Multiguard Protect in soil solution on number of healthy sting nematodes recovered three days after treatment in a laboratory experiment. 40 30 20 10 0 0 500 1000 1500 2000 Multiguard Protect in soil solution (parts per million) Sting nematodes/100 cc (cubic centimeters) 35 30 25 20 15 10 5 0 0 6 12 18 24 30 36 42 48 54 60 66 72 Hours of exposure to Multiguard Protect Sting nematodes/100 cc (cubic centimeters) 080-089_July14_TechwellCuttingEdge copy.indd 85 6/17/14 2:32 PM

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