Growing Turfgrass without Conventional Herbicides: Examining Alternative Strategies Over Two Years.

Dicot weeds such as dandelion (Taraxacum officinale Wigg.), are major pests of turfgrass, competing for space, light, and nutrients. Conventionally, chemical herbicides (e.g. glyphosate, 2, 4-D) have been used to manage these weeds. However, the Ontario Cosmetic Pesticide Ban implemented in 2009, restricts the use of these pesticides in urban settings. This has increased the demand for alternative weed management strategies. This study examines the effectiveness of various weed management treatments as potential alternatives to conventional herbicides for site-preparation and for the management of dicot weeds (post-renovation) in Ontario. Field trials are a designed as randomized complete block, factorial design. Treatments include: untreated control, glyphosate (Roundup), acetic acid (EcoClear), and flame-weeding as site-preparation treatments and untreated control, 2,4-D/mecoprop/dicamba (Par III), chelated iron (Fiesta), lactic acid (Organo-Sol), Sclerotinia minor (Sarritor) and corn gluten meal as post-renovation treatments. Sod is also included as an additional, stand-alone treatment. In year two, an additional treatment of chelated iron, at the minimum label application rate, was included due to its comparability to the standard control, Par III. Weed populations were assessed visually and using a point quadrat over two years. There was no difference in plots treated with site-preparation treatments in year one. Plots treated with post-renovation treatments controls had significantly different weed populations compared with those receiving conventional treatments such as glyphosate followed by Par III in year one. The results of this study suggest that some alternative options are more effective than others, and that some may be as effective for dandelion management as conventional treatments.