Annual Bluegrass and Herbicide Resistance

The cold temperatures and shorter days over the past few weeks have finally allowed the Zoysia grass to go completely dormant. The warmer temperatures in November and December allowed for germination of Annual Bluegrass (Poa) in the dormant Zoysia fairways. In order, to limit the encroachment of this persistent weed, we utilize both pre and post emergent strategies. The Zoysia grass at Hyde Park has been established for over 30 years, thus over time Annual Bluegrass and other weeds can develop resistance to many herbicides therefore reducing the efficacy of the compounds applied.

Jim Brosnan, Ph. D and his team from the University of Tennessee (UT) have done some excellent work on herbicide resistance and strategies to reduce the chances of developing resistant plants. Causes of Herbicide resistance according to the UT website are:

" Weeds developing herbicide resistance is a natural consequence of failing to implement diversified weed management practices. Natural selection will facilitate those plants best adapted to a particular process increase in a population. Most cases of herbicide resistance have evolved following use of the same herbicide for consecutive years without implementing a different weed management practice (other than herbicide) or applying a different herbicide that employs a different mechanism of action."

In order understand if our stratgies to combat Annual Bluegrass in the Zoysia grass fairways are working and are sustainable for the long-term we needed to send samples of the Annual Bluegrass in the fairways to be tested at UT for possible resistance. We spend thousands of dollars each year to make sure Annual Bluegrass does not out compete the Zoysia grass. The good news is that the post emergent strategy of the use of Glyphosate is working well now and currently shows no signs resistance noted in the report below.

Over the next months with the help of Jim Brosnan and his team we will work with the noted recommendations in the report and conduct periodic testing to ensure we continue be economically and environmentally sustainable with our approaches to weed management.

In the next few weeks based upon soil and weather conditions we will apply Glyphosate to the fairways to eliminate the Annual Bluegrass plants that are evident.

If there are any questions or concerns please do not hesitate to contact us grounds@hydeparkcc.com

Thank-you,

Pat O'Brien, MSM

Grounds Superintendent

 

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