You are here:
Response of Pennsylvania native plant species, corn and soybean to tank mixes of dicamba and glyphosate
Citation:
OLSZYK, D. M., T. Griffin, A. Ramsower, T. G. PFLEEGER, E. LEE, AND M. PLOCHER. Response of Pennsylvania native plant species, corn and soybean to tank mixes of dicamba and glyphosate. Presented at Weed Science Society of America Meeting, Portland, OR, February 07 - 10, 2011.
Impact/Purpose:
Crops such as soybean are being genetically modified to be tolerant to multiple herbicides, such as dicamba and glyphosate, in order to allow treatment with several herbicides to control the development of herbicide resistance in weeds.
Description:
Crops such as soybean are being genetically modified to be tolerant to multiple herbicides, such as dicamba and glyphosate, in order to allow treatment with several herbicides to control the development of herbicide resistance in weeds. However, with increased use of multiple-herbicide tolerant plants, non-target plants may be subjected to aerial drift from two herbicides used in combination, instead of just one. Of particular concern are non-target native plants, although crops which have not been genetically modified for tolerance to both herbicides may also be at risk. We evaluated the response to herbicides for four species of native plants found in eastern and mid-western U.S, Andropogon gerardii, Oenothera biennis, Polygonum lapathifolium, and Tridens flavus and non-herbicide resistant soybean (Glycine max, Oregon cultivar14) and corn (Zea mays, Pioneer Pioneer 39J26); which may be at risk from drift of glyphosate and dicamba used on tolerant soybeans. Herbicide concentrations representing aerial drift were used, 0.1 and 0.03 or 0.01 x field application rates (FAR) of approximately 830 and 563 g HA-1 for glyphosate and dicamba, respectively. Plants were grown in small plots in the field to have more realistic plant growth and exposure conditions than may be found in a greenhouse. In general, glyphosate or dicamba at 0.1 x FAR individually reduced plant growth. Lower concentrations of the individual herbicides and herbicide mixes produce some, but inconsistent plant responses. This study indicated that levels of glyphosate and dicamba characteristic of potential herbicide drift concentrations can represent risks to growth of non-target crop and native plants.