Crabgrass control during a hot summer
Crabgrass has been enjoying the high temperatures in Michigan by invading turfgrass areas.
As the weather continues to break all time records across the state, turf has generally been divided into two categories: irrigated and green or dormant and brown. In irrigated areas it is vey likely that crabgrass is making its presence felt. Keep in mind that in contrast to our cool-season turfgrasses that have optimum growing temperatures of about 65 to 75 degrees F, crabgrass is a warm season annual that will thrive in the high temperatures (80-100 F) that Michigan has been experiencing. For dormant areas where irrigation has been applied to ensure that complete crown dehydration and death do not occur, the irrigation may result in some crabgrass emerging. For these areas, controlling crabgrass is probably at the discretion of the turf manager. Some might view the crabgrass as simply providing some green color to an otherwise brown turf. If postemergence crabgrass control is in your plans here’s a herbicide primer.
MSMA is no longer available for selective grassy weed control in turf. Now, there are two options for crabgrass control in cool season turf: quinclorac (Drive) or fenoxaprop-ethyl (Acclaim Extra).
Both products are effective for postemergence control of crabgrass. Quinclorac, however, can boost broadleaf activity when tankmixed with other broadleaf specific herbicides and can provide excellent control of some broadleaves (white clover and dandelion) on its own. Quinclorac will provide excellent control of crabgrass at almost any growth stage (seedling or gorilla-sized) and is very safe when applied to new seedings. Fenoxaprop-ethyl is 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. Unlike fenoxaprop-ethyl, though, quinclorac can be found in many premixed “all in one” herbicides.
Crabgrass emerging in a drought stressed turf.
Dr. Frank’s work is funded in part by MSU’s AgBioResearch.
- MSU Extension’s Drought Resources