Dallisgrass, a perennial pest introduced from South America in the late 1800s, has become one of the most troublesome weeds in the southern and southeastern United States’ turfgrass. Characterized by its rapid growth, coarse texture, and unsightly seedheads, this weed challenges even the most seasoned turf professionals. However, with strategic herbicide application and cultural practices, controlling this persistent invader is achievable.
Identifying Dallisgrass
Dallisgrass can be identified by its bunch-type growth habit, membranous ligule, and short rhizomes that store carbohydrates, making it resilient against physical removal and chemical treatments. It thrives under low mowing heights and is most aggressive from late May through October, necessitating a targeted approach for effective management.
Application Timing
Effective dallisgrass control hinges on the judicious selection of herbicides and impeccable timing. For warm-season turfgrass, experts recommend a sequence of at least three post-emergence applications, beginning in early to late fall when the weed is still actively growing. This timing ensures the herbicides are more effective, as the plant is more susceptible during this period. Notably, pre-emergent herbicides do not affect established dallisgrass plants.
5 Key Herbicides for Controlling Dallisgrass
Effective dallisgrass management in turfgrass often relies on the strategic use of herbicides. Here’s a closer look at some of the key options:
MSMA (Monosodium Methanearsonate)
MSMA is a powerful herbicide that provides 60-80% control of dallisgrass. It’s typically applied twice in the fall and once in the spring for best results. However, due to environmental concerns, its use is restricted to non-residential, commercial, and athletic fields, with specific allowances for golf courses and sod production.
Tribute Total
Tribute Total stands out as it’s labeled for dallisgrass control, not just suppression. It contains a blend of thiencarbazone-methyl, foramsulfuron, and halosulfuron-methyl, offering 60-80% control through three sequential applications. It’s suitable for use in bermudagrass and zoysiagrass.
Revolver (Foramsulfuron)
Revolver is effective for dallisgrass suppression, especially when applied as a spot treatment. It can be used alone or in combination with MSMA for enhanced effectiveness. Revolver is compatible with bermudagrass, buffalograss, and zoysiagrass.
Celsius (Thiencarbazone-Methyl, Iodosulfuron, Dicamba)
Celsius provides dallisgrass suppression and is one of the few options for use in St. Augustine and centipedegrass, albeit with caution regarding turfgrass injury. It works well in combination with Revolver, especially for buffalograss.
Monument (Trifloxysulfuron-Sodium)
Monument suppresses dallisgrass and is notable for its additional control of yellow and purple nutsedge. It’s less effective than some other options but valuable in areas with mixed weed populations. Monument is safe for bermudagrass and zoysiagrass.
Non-Selective Herbicides
Glyphosate is a broad-spectrum, non-selective herbicide, meaning it can kill most plants it contacts, including dallisgrass. It’s important to use glyphosate with precision, particularly in lawns where desirable grasses are present, as it will also kill them if applied directly. Once the dallisgrass is killed, you can use a plugger and start pushing bermuda grass growth to fill in the bare spots.
Non-Chemical Control Methods
For those seeking alternatives to chemical herbicides, physical removal of dallisgrass is possible but challenging due to its extensive rhizome network. Complete removal of the clump and rhizomes is necessary to prevent regrowth. Encouraging the growth and health of the surrounding turfgrass can also suppress dallisgrass proliferation by reducing the space available for weed establishment.
Conclusion
Achieving control over dallisgrass requires persistence, patience, and precision. By applying herbicides at optimal times, considering non-chemical control options, and maintaining healthy turfgrass, professionals can significantly reduce the impact of dallisgrass on their turf. As always, following label directions and considering the environmental impact of any treatment is paramount.
For more detailed guidance and specific herbicide recommendations, professionals are encouraged to consult the comprehensive guidelines provided by experts at The Texas A&M University System. Together, we can maintain the beauty and health of our turfgrass amidst the challenge of dallisgrass control.
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