GIANT SMUTGRASS CONTROL TRIAL B. Justesen, UF/IFAS Extension, Osceola County, Kissimmee, FL, J. Strickland, UF/IFAS Extension, Osceola County, Kissimmee, FL, J. Yarborough, UF/IFAS Extension. Orange County, Orlando, FL, and B. Sellers, UF/IFAS REC. Ona, FL.
Situation: Giant Smutgrass (Sporobolus jacquemontii) is a perennial bunch- type grass that produces over 45,000 seeds per plant per year. Weeds in pastures and rangelands cost ranchers and livestock owners in excess of $180 million annually in Florida. Chemical control for smutgrass is a great option for producers and is important to complete during the rainy month since hexazinone is highly dependent on rainfall. Methods: The smutgrass control trial was completed to determine the percent control of smutgrass using the herbicide hexazinone. The research trial was completed on a 2.0 hectare complete randomized block design with three replications. Each individual plot was 0.093 hectares. The two variables measured a cut and uncut method of application. The blocks represented a cut wipe method with a 30% solution one direction, uncut wipe 30% solution one direction, cut spray 2.34 L/Ha, uncut spray 2.34 L/Ha, uncut control, and cut control. A visual percent control of plant density was completed by multiple agents before, 30 days, and 60 days post treatment. The trial began in August 2018 with recommended rainfall. Results: At 30 days post treatment the cut wipe method with 30% solution showed the largest percent control and the uncut wipe with 30% solution was the second largest percent control method. At 60 days post treatment the cut wipe with a 30% solution exhibited the most control. Conclusion: The trial was analyzed via ANOVA 30 and 60 days post treatment. The P value was less than 0.05 and showed a significant difference between the control and chemical application. Additional measurements will be taken 1 year post application.