Effect of Simulated Drift on Various Plant Species

Much recent research has focused on various environmental conditions and sprayer setup that impact pesticide spray drift potential. Off-target crop injury via spray drift can be more problematic in specific areas due to the close proximity of applications to the wide array of crops grown in certain geographies. Although information is available regarding management practices to minimize pesticide off-target movement, there remains potential for spray drift; consequently, pesticide zero-drift tolerances are not a feasible expectation. Recently, verbiage on pesticide labels regarding drift has been revised to be less subjective for applicator interpretation; however, many labels are vague in describing avoidance of drift into sensitive areas, including bodies of water, wetlands, endangered species habitats, and non-labeled agricultural crop areas including horticultural crop production areas. Much of the research has focused on synthetic auxin mimic herbicides including 2,4-D and dicamba. Indaziflam is a new PRE herbicide for control of annual grass and broadleaf weeds in numerous settings including managed roadsides, railroads, and non-croplands, many of which are in close proximity to horticultural production areas. Greenhouse research was conducted to evaluate the effect of PRE and POST simulated indaziflam or synthetic auxin (aminocyclopyrachlor, clopyralid + triclopyr, or aminopyralid spray drift on the growth of cotton, bell pepper, soybean, squash, tobacco, and tomato. Evaluated spray drift rates were 100, 20, 10, 5, or 2.5% of application rate and plant growth responses varied among herbicides and application timings.