Single Applications of Natural Postemergence Weed Control Options Do Not Provide Effective Ground Ivy Control

Abstract

More information is needed on the turf safety and efficacy of over-the-counter natural weed control products.• A single application of the tested natural weed control options will not control ground ivy.• Homeowners and turf practitioners using natural weed control options will need to differentiate between selective products safe for turf and nonselective products injuring turf before making a purchase/application. AbstractA frequent question is "What 'natural' or 'organic' herbicides (i.e., non-pesticide products) are available for weed control in lawns"?The objectives of this experiment were to determine injury to Kentucky bluegrass (Poa pratensis L.) and efficacy of various natural weed control products on ground ivy (Glechoma hederacea L.). Thirteen "natural" or "organic" treatments were compared to a synthetic postemergence herbicide and a nontreated control. Products were applied in October 2010 and 2011 in West Lafayette, IN. Turf injury was highest for the flame thrower treatment for up to 4 weeks after treatment (WAT). Treatments including Scythe, Worry Free Weed and Grass Killer, BurnOut II Fast Acting Weed and Grass Killer, octanoic acid with or without clove oil, clove oil, and a vinegar cocktail resulted in unacceptable turf injury for 2 to 4 WAT, but then all treatments recovered by 4 to 6 WAT or the following spring. At 3 WAT, ground ivy was initially reduced (75 to 100% control) by the flame thrower, Scythe, BurnOut II Fast Acting Weed and Grass Killer, octanoic acid + clove oil, and mechanical weed control treatments. However, ground ivy coverage reductions were temporary, as a single fall application did not provide adequate long-term control (>50%), and all treatments were similar the following spring, providing an average of only 22% ground ivy control. Single applications of the tested natural weed control options do not adequately control ground ivy with the majority of the products causing unacceptable turf injury.

Alternative and Low-Use-Rate Herbicides Offer Similar Levels of Weed Control to Current Standards in Turfgrass Lawns in the Upper Midwest

“…Two applications were required to control ground ivy, and other weeds like broadleaf plantain ( Plantago major ) were not effectively controlled. Patton et al (2019a) also tested an iron chelate herbicide for control of ground ivy and found that a single application only resulted in 5% control relative to the non‐treated control 32 weeks after treatment. Other biologically based selective herbicides that use plant pathogenic fungi or bacteria for turfgrass weed control do exist but are rare in the turfgrass market.…”

Exploring Natural Alternatives for Annual Bluegrass Control

“…From this study, several non-synthetic chemical products tested could potentially provide some short-term annual bluegrass burndown. However, results were intermediate at best with little to no long-term control from most products evaluated, similar to the low weed control efficacy observed after applying non-chemical products in other turfgrass systems [8]. None of the products tested appear to provide acceptable commercial control with only a single application for this winter annual weed.…”

“…Certain products also caused short-term (1 to 2 weeks) undesirable turf phytotoxicity. Other research has found similar, non-chemical products have caused injury to desired turf as well [8,11]. Similar visual burndown is often observed after applying non-selective herbicides such as glyphosate, diquat, or glufosinate [3].…”

Strategies for reducing inputs and emissions in turfgrass systems

“…While fraise mowing is gaining some adoption, a cost analysis compared to other pest control strategies does not yet exist (Carroll et al., 2021) nor has work been done to quantify the loss of C and N from soil removed or GHG emissions. While fraise mowing is a novel cultural control tactic, other nonchemical control tactics such as solarization (Peachey et al., 2001) and flaming (Patton et al., 2019) are likewise likely to have hidden carbon costs (HCC) much greater than pesticides. As such, carefully considering the inputs and emissions of control strategies is needed before selecting the best approach.…”