In one of our Using Pesticides Wisely trainings, an elderly gentlemen with a deep voice and powerful persona put me on the spot and wanted to know an exact distance he needed between his peaches and the neighbors auxin sprays. Boy, that was a tough one. As many of you have attended our trainings, you understand that there are at least 15 factors that influence off-target movement and all of these factors are interacting with each other constantly. In fact, science would suggest that drift will never be the same even in two adjacent fields due to land terrain; much less the changing environment. I am certain, no one with any scientific drift experience will ever provide a specific distance number as it will never ever ever be correct.
So what does this pillar of the peach industry do? First, it would be great if he would communicate with his neighboring growers that peaches are very sensitive to the auxin herbicides (sensitivity charts are below and can be obtained at www.gaweed.com). Next for those applying 2,4-D or dicamba in crop legally, you have been provided detailed data from seven UGA large acreage drift experiments to at least help you better understand potential drift distances as influenced by various factors (tip, wind speed, boom height, etc.; your agent has this information if needed). Although this data does not give the answer, it at least improves your awareness. Third, remember for those of you next to sensitive crops/plants/neighbors, we do have sound weed management programs excluding auxin herbicides that can be implemented effectively.
And finally he clearly asked me a direct question of “what would I do”? Well obviously I would not spray with the wind blowing toward any sensitive crop. Additionally, I will continue to stick with my statement that if I could stand on-top of my highboy and see a super sensitive crop with binoculars, then I would not spray an auxin during summer time even if the wind is blowing away from the crop…….the risk simply does not equal the reward to me based on our current knowledge or lack thereof in regards to auxin volatility when used on large-scale acres and because I know I have other successful options for those specific fields.
The auxin-technologies offer a wonderful weed management program but only when off-target issues are not a concern. Also, don’t forget to always follow labels including the buffers provided on each in-season auxin label needed to protect our endangered species.