Methiozolin is a selective herbicide that has been reported to control annual bluegrass in creeping bentgrass putting greens. Golf course managers frequently tank-mix fertilizers with herbicides to reduce time and labor, but no information is available regarding such mixtures with methiozolin. Research was conducted to evaluate methiozolin for annual bluegrass control and creeping bentgrass safety when tank-mixed with ammonium sulfate or iron sulfate. Mixtures with ammonium sulfate did not influence annual bluegrass control while they did reduce creeping bentgrass injury in some instances. Mixtures with iron sulfate varied by experimental run but annual bluegrass control was either similar or increased while creeping bentgrass injury did not vary. Paclobutrazol was included as an alternative agrochemical comparison for annual bluegrass management; its application resulted in similar control and injury with and without iron sulfate addition, and injury and control were similar to methiozolin at appropriate rates. While some differences were observed, overall annual bluegrass and creeping bentgrass response to methiozolin was not affected by tank-mix nutrient partner relative to methiozolin applied alone.

Combinations of MSMA (Monosodium methanearsonate) with either methazole [2-(3,4-dichlorophenyl)-4-methyl-1,2,4-oxadiazolidine-3,5-dione] or metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazin-5(4H)-one] were applied at various rates for postemergence control of fully developed goosegrass [Eleusine indica (L.) Gaertn.], a major weed grass in bermudagrass [Cynodon dactylon (L.) Pers.] turf. Two applications of MSMA at 2.24 kg/ha applied in combination with either methazole or metribuzin at 0.14 kg/ha controlled 96 to 98% of the goosegrass and it was as effective as methazole (1.12 kg/ha) or metribuzin (0.56 kg/ha) applied alone. Two applications of methazole (1.12 kg/ha) or metribuzin (0.56 kg/ha) had lower quality ratings (28 and 39, respectively) on bermudagrass putting green at 2 weeks after treatment than combinations of MSMA (2.24 kg/ha) with either methazole (0.14 kg/ha) or metribuzin (0.14 kg/ha) (54 and 59, respectively). The initial injury from combination treatments was not severe and turf recovered within 3 to 4 weeks.

Annual bluegrass (Poa annua L.) was controlled in bermudagrass [Cynodon dactylon (L.) Pers.] turf when ethofumesate [(±)-2-ethoxy-2,3-dihydro-3,3-dimethyl-5-benzofuranyl methanesulfonate] was applied at 1.1 kg/ha in October and again in November, but not when applied in February and March. A single, October ethofumesate treatment, did not affect spring growth of nonoverseeded bermudagrass, but the growth of selected cultivars was delayed slightly from October + November treatment. Turf growth was severely delayed for all bermudagrass cultivars when ethofumesate treatments were delayed until February and March. The October and November ethofumesate treatments reduced the quality of overseeded perennial ryegrass [Lolium perenne (L.) ‘Medalist VI’] slightly, but did not injure it permanently and the turf recovered fully. The transition from ryegrass back to bermudagrass turf was good in the spring regardless of ethofumesate treatment. Even though turf cover was excellent throughout the transition period, bermudagrass cover during June and July was less when ethofumesate was applied in October than when application was delayed until after bermudagrass became dormant.

The presence of weeds during bermudagrass putting green establishment can reduce growth and turf quality. Three field experiments were conducted in Georgia to investigate efficacy of dimethenamid, S-metolachlor, and oxadiazon on the establishment of ‘TifEagle’ bermudagrass from sprigs. Dimethenamid at 0.85 and 1.7 kg ai ha−1, S-metolachlor at 1.1 and 2.2 kg ai ha−1, and oxadiazon at 1.1, 2.2, and 4.4 kg ai ha−1 did not reduce bermudagrass cover from the untreated after 8 wk. S-metolachlor at 4.4 kg ha−1 was the only treatment that reduced sprig cover from the untreated after 12 wk. All S-metolachlor and oxadiazon treatments provided excellent (≥ 90%) green kyllinga control by 8 wk after treatment (WAT) while dimethenamid at 0.85, 1.7, and 3.4 kg ha−1 provided 78, 85, and 92% control, respectively. Dimethenamid treatments provided poor control (< 70%) of spotted spurge but fair control (70 to 79%) was achieved from S-metolachlor at 4.4 kg ha−1 and oxadiazon at 2.2 and 4.4 kg ha−1 by 8 WAT. Overall, low to middle rates of the herbicides tested appear to temporarily inhibit TifEagle bermudagrass sprig establishment but high rates of dimethenamid and S-metolachlor may reduce cover from the untreated.

Annual bluegrass is a troublesome weed in golf course putting greens. The objective of this research was to evaluate creeping bentgrass putting green tolerance to bispyribac-sodium tank-mixed with paclobutrazol in the transition zone. Field trials with four replications were conducted in Oklahoma during 2009 and 2010 and in Missouri during 2010. The results of this study suggest that tank-mixing bispyribac-sodium with paclobutrazol may discolor creeping bentgrass putting greens but will not reduce turf quality below acceptable levels. Normalized vegetative difference index readings indicated no treatment differences in turf greenness at 4 and 8 wk after initial treatment. Weekly application of bispyribac-sodium at 12.4 g ha−1 or biweekly application at 24.8 g ha−1 alone or with monthly applications of paclobutrazol at 224 g ha−1 did not cause unacceptable injury to creeping bentgrass putting greens during the spring.

Silvery threadmoss naturally reproduces through spore and bulbil production, both of which have potential to be controlled prior to establishment. Studies have not evaluated effects of turf protection products on moss protonema or gametophyte growth from spores or bulbils; consequently, most moss is controlled POST on putting greens. Initial studies were performed to determine the optimal growth temperature for spores and bulbils in sterile culture. Protonemata from spores grew optimally at 29.5 C and gametophytes from bulbils grew optimally at 22.5 C. Three subsequent in vitro studies were conducted to evaluate effects of turf protection products on moss development from spores or bulbils in axenic culture at a constant 24 C. Carfentrazone, which effectively controls mature silvery threadmoss gametophytes POST, also reduced green cover of moss protonemata and gametophyte production from spores and bulbils. All combinations with carfentrazone reduced area under the progress curve (AUPC) for green cover of moss for both spores and bulbils by 80% or more by 3 wk after treatment. Sulfentrazone, oxyfluorfen, oxadiazon, saflufenacil, flumioxazin, and pyraflufen-ethyl reduced AUPC of moss equivalent to carfentrazone for both propagule types. The two fosetyl-Al products, phosphite, and mineral oil caused an increase in silvery threadmoss cover between 22 and 113% of the nontreated for spores; however, only methiozolin positively influenced AUPC (90.2%) compared to the nontreated for bulbils. Though silvery threadmoss is typically targeted POST on putting greens, there are products that can provide PRE control, including the industry standard of carfentrazone. These data suggest that differences may occur between turf protection products in their ability to suppress silvery threadmoss establishment from spores or bulbils.