Dallisgrass is currently emerging in southern Indiana. This perennial grassy weed is almost identical in appearance to crabgrass and can be problematic in the southern half of Indiana. Dallisgrass is often mistaken for crabgrass but it has slightly less hairy leaves than crabgrass, a longer ligule and slightly wider leaf blades (see photos). Dallisgrass is a perennial that regrows from crowns and thus preemergence herbicides do not effectively control it, which is another clue to help you distinguish dallisgrass from crabgrass. If you applied preemergence herbicides this spring and still have what appears to be crabgrass emerging, it could be dallisgrass. Additionally, dallisgrass is not susceptible to typical postemergence crabgrasss herbicides like Acclaim, Dimension, or Drive. Controlling dallisgrass is at best difficult. Two applications of MSMA about 14 days apart is the standard recommendation but control is marginal at best. Roundup is the most effective control. Few herbicides are labeled for dallisgrass in part because it is tough to research and it is not a widespread problem. We are working with some new chemistry that has the potential of controlling dallisgrass, but need your help. If you have an area (lawn, fairway, athletic field, etc) of 1000 ft2 or more with fairly consistent dallisgrass, we would like to use it for testing. Please contact me at zreicher@purdue.edu if you know of an area that might work.
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