Roundup for Lawns
It is weed season. Actually, it can almost always be weed season, depending on your definition of a weed. In fact, one definition of a weed is “any plant in the wrong place”, and many folks reach for the container of herbicide that is most likely found in with their gardening supplies to deal with the unwanted plant. Often the product at hand contains glyphosate, under one of many trade names. Glyphosate is a broad spectrum herbicide formulated to control BOTH broadleaf and grass weeds.
One of the brand names that is best known is “Roundup®”. However, a new product that has been released under the “Roundup®” banner may have some very unfortunate unintended consequences if the user does not read the product label very carefully to be absolutely sure they are applying the right product with the appropriate chemistry to address the problem issue they wish to solve. The following article written by NCSU experts Patrick Maxwell, Travis Gannon, and Fred Yelverton will help clarify the situation, and hopefully keep consumers on the right garden path (please excuse the terrible pun, but I couldn’t resist).
“Roundup®” and “Roundup® For Lawns” Now Available in the Marketplace – Confused Yet? Written by By Patrick Maxwell, Travis Gannon, and Fred Yelverton
Recently, a new product “Roundup® For Lawns” was granted registration by the US EPA and has generated a lot of attention, concerns and questions largely because of the trade name. Many are asking, “if I apply this product to my lawn, will it not kill my grass”? The answer is no, because Roundup® For Lawns does not contain the active ingredient glyphosate which is the active ingredient in Roundup; however, it is a source of confusion and individuals should be aware and pay close attention to the product they select. So, if Roundup® For Lawns does not contain glyphosate, why is this new product being marketed under the Roundup® portfolio? This is likely due in part to marketing efforts.
Roundup® is arguably the most recognized herbicide trade name ever and has been synonymous with the active ingredient glyphosate since its introduction in the 1970s. Glyphosate is a broad spectrum nonselective herbicide, meaning it controls many desirable and weedy species compared to selective herbicides which control specific weed species while not adversely affecting desirable species. Numerous products have been distributed under the trade name Roundup® for use in agricultural and consumer sectors, yet glyphosate has remained the primary active agent in all prior Roundup® products until Roundup® For Lawns was registered.
Several formulations of Roundup® For Lawns are currently registered. Although there are several formulations registered, many big-box stores in the region are carrying two formulations, one recommended for southern (Roundup for Lawns4) and one for northern turfgrass species (Roundup for Lawns1). Each formulation contains includes dicamba, a synthetic auxin used for broadleaf weed control and sulfentrazone, a PPO (protoporphyrinogen oxidase) inhibitor marketed primarily for nutsedge and kyllinga suppression but offers activity on some problematic broadleaf weeds (e.g. ground ivy, wild garlic, etc.). Additional ingredients in the southern version include, 2,4-D, another common synthetic auxin used for select broadleaf weed control and penoxsulam, an ALS (acetolactate synthase) inhibitor offering control of select broadleaf weeds. Not surprising, PBI Gordon produces a product (Avenue® South) that contains the same four active ingredients found in the southern version at five-times the active ingredient concentrations. Additional ingredients in the northern version include, MCPA a synthetic auxin used for broadleaf weed control and quinclorac a cellulose biosynthesis inhibitor offering post-emergent crabgrass control and excellent control of many troublesome broadleaf weeds (e.g. dichondra, dollarweed, etc.).
Further complicating matters, both southern and northern formulations of Roundup® For Lawns are available at many local home improvement stores in North Carolina. Determining which product is right for your situation is critical to achieving desired results and minimizing turfgrass damage. This situation offers an excellent lesson in the importance of distinguishing the difference between an active ingredient and a product trade name. We often treat the two synonymously, but as evident with Roundup® compared to Roundup® For Lawns understanding the difference and applying the correct product is essential to avoid potentially detrimental consequences. In conclusion, PLEASE make certain you purchase the intended formulation and carefully read and follow all label instructions and guidelines when applying any pesticide.
Patrick Maxwell is a graduate student in the Crop and Soil Science Department at NC State University under the direction of Drs. Rich Cooper and Travis Gannon. Travis Gannon is an Assistant Professor in the Crop and Soil Science Department at NC State University. Fred Yelverton is a Professor and Extension Specialist in the Crop and Soil Science Department at NC State University.