Cover Story
Weed Control
Lessons Learned in 2018
By Jim Brosnan, Ph.D., Greg Breeden, and José J. Vargas, University of Tennessee
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ach year the turfgrass weed science program at the University of Tennessee conducts hundreds of research trials in the field, greenhouse, and laboratory. Despite having an array of different objectives, all of these trials have a singular focus: to help turfgrass managers with weed management issues. The article below outlines key lessons learned in our program last year that will hopefully be of use to turfgrass managers in the coming season.
Lesson #1 – Explore Weather Data Mother nature certainly threw turfgrass managers across Tennessee many curveballs in 2018. The year began with air temperatures measuring much higher than historical averages leading to spring emergence of warm-season turfgrasses
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(and weeds) occurring earlier than normal. Air temperatures fell in April, measuring nearly 10 degrees cooler (on average) than April 2017. Warming in 2018 (as measured by growing degree day accumulation) was higher than the previous two seasons and this period of warming continued into the fall. A detailed breakdown of erratic weather across Tennessee in 2018 is available at: https://medium.com/@UTTurf Weeds/several-curveballs-from-mothernature-in-2018-d487c9b2015d. Irregular weather patterns will not only affect the severity of weed infestations in warm- and cool-season turfgrasses but the efficacy of several herbicide treatments as well. That said, University of Tennessee Extension is here to help. Should turfgrass managers encounter oddities during the 2019 season, they are highly encouraged to contact the University of Tennessee for
TENNESSEE TURFGRASS April/May 2019 Email TTA at: info@ttaonline.org
a breakdown of climatic conditions that may help explain the situation.
Lesson #2 – Know Your Poa One of the biggest lessons learned last year is that Poa annua populations across the state of Tennessee are very different from one another. Thanks to support from the Golf Course Superintendents Association of America (GCSAA) and Tennessee GCSAA, our team is currently conducting a survey of Poa annua across the state. Efforts have allowed us to study 72 different populations randomly selected during spring 2018 from golf courses in East, Middle and West Tennessee that had either bermudagrass (Cynodon spp.) or zoysiagrass (Zoysia spp.) as a primary turfgrass species. Things we’ve learned studying these populations include:
