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November 15, 2022

A Closer Look at Poa annua

Neutralize Poa pressure and prevent Herbicide Resistance with Negate

The never-ending fight against Poa annua continues to produce populations that have developed resistance to one or more classes of herbicide options. Relying on traditional preemergent applications alone is practically begging for the development of resistance, but combining the preemergent approach with postemergent follow-ups is ideal.

A preemergent herbicide such as Quali-Pro Prodiamine is a great preventive strategy prior to the arrival of ideal conditions for seed germination: soil temperatures falling to 70°F. As with any herbicide, if even a few individual plants have developed resistance to your selected mode of action, they can begin passing along this trait to the next generation if allowed to mature, flower, and add to the seed bank. Over time, this can eliminate an entire class of herbicides as viable options. Cleaning up any emerged poa plants is therefore an essential means of preventing resistance from being passed along. When in the dead of winter on fully dormant bermudagrass, a non-selective approach can be chosen, but in the meantime, those poa plants are maturing and becoming harder to control. To clean up those new plants and a wide spectrum of broadleaf winter weeds that are likely also emerging, Quali-Pro Negate is an excellent choice.


Labeled for golf, sports, commercial, and residential turf, Negate combines metsulfuron-methyl and rimsulfuron in one convenient bottle to cover one acre. These sulfonylurea active ingredients provide control by blocking the activity of an enzyme involved in the production of certain amino acids. This disruption prevents the plant from making all the necessary proteins to keep its metabolism going, resulting in death of susceptible species. This convenient package eliminates tank mixing and takes the guesswork out of measuring smaller quantities of the low-rate use ingredients. Negate also makes a great spring transition tool in overseeded turf that is more cost effective than other options. It can also be used to selectively remove bahiagrass from bermudagrass and zoysia in areas where it may be encroaching.


Late-fall use of Negate also helps preserve the efficacy of nonselective options such as glyphosate combined with Quali-Pro Flumishield (available soon) by limiting the number of plants that are exposed to those winter application active ingredients. This type of multi-pronged approach for Poa management is considered the most ideal for preserving your effective herbicide options in the long run. So reach for Negate as the “early post-” app in your defense and keep your preemergent and winter/late post- options alive.


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Ian Rodriguez, Ph.D.

Ian Rodriguez Technical Service Manager Quali-Pro

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