Herbicide update: what’s new for 2018?

A hot topic of conversation among all turf managers each winter is what “new” products will be entering the marketplace in the coming year. Many scour the trade show floor at the Sports Turf Managers Association Conference visiting with vendors from across the globe about what new technologies they may have available in the coming year that will help in improving field conditions.

From an herbicide standpoint, there hasn’t been a true “new” product for more than 30 years. The last new mode of action (i.e., mechanism an herbicide uses to eradicate a weed) was discovered in the 1980s in hydroxyphenylpyruvate dioxygenase (HPPD) inhibition. This mechanism has since been commercialized in turfgrass herbicides such as Tenacity (active ingredient, mesotrione) and Pylex (ai, topramezone) that cause bleaching of green leaf tissue in susceptible weeds.

What we regularly see each year are new entries into the turfgrass marketplace that employ existing modes of action, often formulated in novel combinations that deliver unique attributes to turfgrass managers. This will certainly be the case in 2018 as several new herbicides are scheduled to enter the marketplace for use on both warm- and cool-season turfgrass athletic fields.

This article will provide a brief overview of some of the new herbicides slated to enter the turfgrass marketplace later this year. Turfgrass managers should consult their local University extension specialist for more information about how these technologies best fit into athletic field management in their region.


Vexis is a trademarked term for pyrimisulfan, a new herbicidal active ingredient from PBI-Gordon Corporation. Trade names for herbicides containing Vexis have not been made publically available but field managers will likely see “powered by Vexis” messaging associated with these products. Vexis is an acetolactate synthase (ALS) inhibiting herbicide that enters plants via both root and shoot absorption. Vexis will be available in combination with other herbicides.

In the transition zone and southern United States, field managers will see a combination of Vexis + penoxsulam (another ALS-inhibiting herbicide) for use on athletic fields. This combination will have postemergence activity on array of broadleaf weeds and sedge species. It should be noted that penoxsulam can be injurious to perennial ryegrass (Lolium perenne), which will limit use of this product on overseeded bermudagrass (Cynodon spp.) football or baseball fields. Combinations without penoxsulam are also being developed for use on cool-season fields that contain perennial ryegrass in mixtures with other species.

A unique attribute of Vexis products is that they are formulated on granular carriers. Granular application may be particularly useful in situations where spray applications are discouraged (e.g., certain school grounds, etc.). Our research team at the University of Tennessee has evaluated Vexis + penoxsulam on an inert granule as well as on fertilizer. In both cases, these products can be applied to dry turf (without dew present), which is abnormal for granular herbicides. Usually granular herbicides need to be applied with dew present to adhere to leaf tissue and enter weed foliage. Root absorption of both Vexis and penoxsulam allow for weed control to be achieved without this requirement for dew. However, adequate soil moisture at the time of application is needed for Vexis products to perform optimally. Moreover, applications of Vexis will need to be watered in (via irrigation or rainfall) within 48 hours of treatment.

Federal labeling for Vexis use in turfgrass has been submitted to the US Environmental Protection Agency (EPA) and is awaiting approval.


Relzar is a new herbicide mixture from DowDupont that contains Arylex Active (ai, halauxifen-methyl) and the florasulam, an ALS inhibitor. Arylex Active is the first member of a new class of synthetic auxin herbicides, the arylpicolinates (HRAC group O, WSSA group 4), with unique binding affinity that is different from other auxin herbicides. Formulated as a water dispersible granule, Relzar is designed to control broadleaf weeds in nearly all warm- and cool-season turfgrasses used on athletic fields. The use rate of Relzar will be 0.72 oz/A for all labeled weeds. Relzar offers turfgrass managers a broadleaf weed control option that does not contain 2,4-D and that is also rainfast within 1 hour after application. Relzar is scheduled to become available in late 2018 after receiving approval from EPA.


GameOn is another new herbicide mixture from DowDupont that contains Arylex Active (ai, halauxifen-methyl) in combination with the synthetic auxin herbicides 2,4-D choline and fluroxypyr. GameOn will be labeled for use on all major cool-season turfgrasses, as well as bermudagrass and zoysiagrass (Zoysia spp.), at rates ranging from 3 to 4 pts/A. GameOn will be labeled for control of more than 100 different broadleaf weeds and will offer athletic field managers a broadleaf herbicide mixture that has a “Warning” signal word on the product label; this is unique given that many 2,4-D containing herbicides have a “Danger” signal word, indicative of greater toxicity. GameOn is scheduled to become available in late 2018 after receiving approval from EPA.


SwitchBlade is a new liquid herbicide mixture from PBI-Gordon that contains the synthetic auxins fluroxypyr, dicamba, and halauxifen-methyl. This herbicide can be used postemergently to control an array of different broadleaf weeds in nearly all warm- and cool-season turfgrasses used on athletic fields. Rates will range from 1.5 to 4 pt/A, with a maximum application rate of 8 pt/A per year. The herbicide is rainfast within 1 hour after application. SwitchBlade will offer turfgrass managers a broad-spectrum herbicide mixture that does not contain 2,4-D; this may become important as public pressure and potential legislation against 2,4-D use increases in certain parts of the country. Federal labeling for SwitchBlade use in turfgrass has been submitted to the EPA and is awaiting approval.

Dismiss NXT

Dismiss NXT is a postemergence herbicide mixture from FMC Corporation that combines carfentrazone and sulfentrazone in a 1:9 ratio. Dismiss NXT can be used to control yellow nutsedge ([START ITAL]Cyperus esculentus[END ITAL]) postemergence and manage kyllinga ([START ITAL]Kyllinga[END ITAL] spp.) applications via sequential applications. This herbicide is labeled for use on bermudagrass at rates of 10.2 to 15.25 fl oz/A; use rates on cool-season turfgrass are slightly lower, ranging from 5.1 to 10.2 fl oz/A. When applied to bermudagrass fields overseeded with perennial ryegrass, a maximum application rate of 5.1 fl oz/A is recommended. A unique attribute of Dismiss NXT is rapid activity after application. Treated weeds will show symptoms within 7 to 10 days after application.

Jim Brosnan, former Technical Editor of SportsTurf, was honored at the STMA Conference in January by receiving the Dr. William H. Daniel Founders Award, which recognizes an individual who has made significant contributions to the industry through research, teaching or extension. Congratulations, Jim!

Jim Brosnan, PhD, is an Associate Professor in the Plant Sciences Department at the University of Tennessee and leader of their Weed Diagnostics Center; jbrosnan@utk.edu; Twitter- @UTturfweeds.