Smutgrass is a serious weed problem in many bahiagrass pastures of the southeastern U.S. particularly Florida. This weed is a perennial bunch-type grass named for the dark-colored fungus which is often found in the seed heads. The reddish seeds, which may remain stuck to the seed head for sometime after maturing, are spread mainly by adhering to livestock, or by water, and may remain viable for two or more years.

Smutgrass produces in excess of 45,000 seeds per plant with over 1400 seeds per head. Seed production takes place throughout the growing season. Smutgrass plants are generally unpalatable to cattle. However, cattle will readily consume the regrowth of smutgrass for up to two weeks following a burn or mowing.

Research at Ona has indicated that mowing does not control smutgrass, but does help spread the seed. Under continuous close mowing, plant diameter decreased but number of plants increased. When mowing stopped, plants recovered to their former density.

Early herbicide research with Dalapon provided 85 to 90 percent smutgrass control. However, in recent years this chemical was removed from the market.

Recent studies at Ona indicate broadcast spraying in mid-summer (July-August) at 0.5 lb/A active Velpar, plus 0.25 percent X-77 spreader resulted in 90 to 100 percent smutgrass control when growing in association with bahiagrass. These results did not require mowing of smutgrass prior to herbicide application.

However, applying 0.5 lb/A active Velpar plus 0.25 percent X-77 spreader early (mid-June) in the growing season resulted in poor smutgrass control.

Increasing the rate of Velpar from 0.5 to 0.75 or 1.0 lb/A active, provided 90 to 100 percent smutgrass control when applied from mid June to early September on unmowed smutgrass plants. However, these treatments will increase the cost/A from 50 to 100 percent.

Mowing smutgrass and allowing plants to regrow back to a six to 12 inch height prior to spraying with Velpar resulted in little increase in smutgrass control over non-mowing. These data indicate that a spray application of 0.5 lb/A active Velpar plus 0.25 percent X-77 spreader during the warm-rainy season of July and August resulted in 90 to 100 percent smutgrass control, with no previous mowing required.