EAST LANSING, Mich. – The best defense against crabgrass invasion is maintaining a healthy, dense turf stand by mowing high and fertilizing throughout the season. Even so, crabgrass will almost certainly raise its ugly head in some of the lawns under your care.
Kevin Frank and Aaron Hathaway of Michigan State University Extension recently shared this short primer on managing postemergent crabgrass in its extension e-newsletter. Postemergence control is generally more effective when crabgrass is younger before it has tillered. As crabgrass matures, postemergence control becomes more challenging and multiple applications spaced 2-3 weeks apart are necessary to achieve control.
MSMA is no longer available for selective grassy weed control in lawns/commercial turf. However, there are several options for controlling crabgrass in cool-season turf: Drive (a.i. quinclorac)), Acclaim Extra (a.i. fenoxaprop-ethyl), Tenacity (a.i. mesotrione), and Pylex (a.i. topramezone). All effective for postemergence control.
Homeowners and other DIY’ers will find that products containing quinclorac that store shelves typically contain quinclorac. Quinclorac provides excellent control of crabgrass at almost any growth stage (seedling or mature) and is very safe when applied to new seedings. Quinclorac, mesotrione and topramezone also have the added benefit of providing control of some broadleaves such as white clover and dandelion. Fenoxaprop-ethyl is generally not as effective on larger or more mature crabgrass as quinclorac, but can provide excellent control of other grassy weeds, such as goosegrass, that are not effectively controlled by quinclorac. Topramezone also provides control of goosegrass.
Always read, understand and follow the label directions. Mention or exclusion of specific products does not represent an endorsement or condemnation of any product by Michigan State University Extension, stresses the e-newsletter.