Yellow nutsedge and irrigation

Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.  

My personal observations of turf stress indicators including how many consecutive days the air conditioning has been on and is the turf over the septic field brown yet, have been generally absent this summer. Although many do not consider it a blessing to have high temperatures in the 60’s the week prior to the 4th of July weekend, the cool season turf that makes its home in this state has been generally thriving in these weather conditions. Weeds have dominated most of the writings in this column this year as there really haven’t been too many other stress maladies to focus on.

Continuing on the weed trend this week, I’ve been noticing that yellow nutsedge has been popping up in turf. Control options for the homeowner are rather limited; look for products with the active ingredient sulfentrazone. Yellow nutsedge control options for professional applicators include Certainty (a.i. sulfosulfuron) and Sedgehammer (a.i. halosulfuron). Repeat applications will likely be required to achieve control. As with any herbicide applications at this time of year, be cautious of applications to turfgrass that is under drought or heat stress, even with the relatively cool temperatures, the soil is drying out in many areas and the turf is starting to show some stress. General recommendations are to avoid herbicide applications when temperatures are above 80° F due to the risk of burning the turf.

It’s been a great year for irrigation systems as any gaps in coverage have been covered up by the rain. If the weather pattern gives us some more dry days, poor irrigation uniformity will start to display itself with green and brown circles in the turf where the irrigation is not uniform. It never hurts to actually watch the irrigation system every now and then and not just assume it’s working perfectly. Soil differences across an area can result in visual differences in turfgrass very similar to those seen with poorly functioning irrigation systems. Although we would all like to think we have a very uniform soil type to grow our turf and landscape plants in, that is often not the case.

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