John H. McCalla

Tolerance of 'Riviera' Bermudagrass to MSMA Tank-Mixtures with Postemergence Herbicides During Establishment from Seed

Seeded bermudagrass (Cynodon dactylon L. Pers.) cultivars are rapidly gaining popularity in the turfgrass industry. Management programs need to be developed for the proper establishment and maintenance of these seeded cultivars. The objective of this study was to determine the tolerance of seedling ‘Riviera’ bermudagrass to a range of postemergence herbicides. Herbicide treatments were applied at 2 and 4 weeks after emergence and included metribuzin + MSMA, triclopyr + clopyralid + MSMA, clopyralid + MSMA , flazasulfuron + MSMA, foramsulfuron + MSMA, trifloxysulfuron-sodium + MSMA, quinclorac + MSMA, 2,4-D + dicamba + mecoprop + MSMA, and quinclorac. Herbicide injury and turfgrass coverage rates were monitored for 4 weeks after treatment. Treatments that caused significant injury to the seedling turf included metribuzin + MSMA and triclopyr + clopyralid + MSMA. Most of the herbicide combinations tested in these trials caused some level of turfgrass injury, but this injury was generally shortlived and did not significantly reduce the rate of turfgrass coverage. The results of this study indicate that a range of herbicide combinations can be safely used on seedling bermudagrass to control problematic weeds during establishment.

Herbicide Tolerance of Buffalograss

Buffalograss (Buchloe dactyloides (Nutt.) Engelm.) is a low-maintenance turfgrass alternative in many parts of the United States. When buffalograss is seeded, competition from weeds can significantly delay establishment. Additional research is needed on buffalograss seedling tolerance to herbicides, including newer herbicides such as the sulfonylurea family. Research was conducted in 2004 near Mead, NE and in Fayetteville, AR to evaluate both preemergence and postemergence herbicide tolerance of seedling buffalograss. Foramsulfuron, imazapic, metsulfuron, MSMA, oxadiazon, pendimethalin, prodiamine, quinclorac, rimsulfuron, simazine, and trifloxysulfuron-sodium were applied to seedling buffalograss as per warm-season grass label rates. All herbicides evaluated exhibited moderate to excellent safety for newly established buffalograss. Some initial, moderate injury may be expected with foramsulfuron and imazapic, but any injury observed 4 weeks after application was deemed acceptable for all herbicides evaluated. In general, buffalograss is tolerant to a majority of the herbicides used with other warm-season grasses. In addition, buffalograss exhibited adequate seedling tolerance to the sulfonylurea herbicide family.