Crabgrass control during a hot summer

Posted on July 11th, 2019
Dr. Kevin W. Frank
Michigan State University
Thanks for your continued support of the MSU Turf Team and the Michigan Turfgrass Foundation. As the summer heat ramps up, we continue preparation for the Michigan State Field Day on August. 14 at the Hancock Turfgrass Research Center. There will be morning research tours and afternoon diagnostic walks and tours. REGISTER now to ensure your spot.

Postemergence Crabgrass Control 

The cool, wet start to the year seemingly changed over night with high temperatures and humidity arriving with a vengeance in late June and early July. Following the high temperatures, crabgrass is now surging in many turf areas.

Keep in mind that in contrast to our cool-season turfgrasses that have optimum growing temperatures of about 65-75 degrees Fahrenheit, crabgrass is a warm-season annual that will thrive in the high temperatures of 80-100 F. So as cool-season turf growth has slowed in the last several weeks, crabgrass is now exploding in growth. If post-emergence crabgrass control is in your plans, here’s a herbicide primer. Herbicides will be primarily referred to by their active ingredient. 

There are two main options for post-emergence crabgrass control in cool-season turf: quinclorac (Drive XLR8) or fenoxaprop-ethyl (Acclaim Extra). Both products are effective for post-emergence control of crabgrass. However, there are also some key differences between these products (see table):

  • Quinclorac can boost broadleaf activity when tank-mixed with other broadleaf-specific herbicides, especially phenoxies like 2,4-D and MCPP.
  • Quinclorac can provide excellent control of some broadleaves, like white clover and dandelion, on its own.
  • Quinclorac can miss excellent post-emergence crabgrass control when crabgrass is at the two-to-three tiller stage.
  • Add a methylated seed oil to quinclorac to improve efficacy.

The entire article can be viewed at

Dr. Frank’s work is funded in part by MSU’s AgBioResearch.

This article was published by Michigan State University Extension. For more information, visit To have a digest of information delivered straight to your email inbox, visit To contact an expert in your area, visit, or call 888-MSUE4MI (888-678-3464).

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