Written collaboratively by Eric Jones, Philip Rozeboom, Jill Alms, and David Vos.
I am reluctant to write this article, but I think a cautionary message being conveyed is important to remind everyone that no matter how busy you are during the season, it is important to double check some things before spraying.
Every growing season you hear a tale of (or sometimes experience) spraying the wrong herbicide on a crop by the sheer chance that you grabbed the wrong herbicide jug or sprayed an incorrect variety. This unfortunately happened to the SDSU Extension Weed Science program this year. The program is currently conducting a study investigating different herbicide application timing in sunflower. One treatment was a comparison looking at a standard postemergence application: tibenuron (Express: 1 ounce per-acre) and clethodim (Select Max: 16 fluid ounces per-acre). Approximately one week after the herbicide application, I was driving by to look at the study. I was no more than 200 yards away when I noticed and said out loud, “Yep! Those are Clearfield sunflowers!” Express sunflowers can tolerate being treated with Express herbicide, but Clearfield sunflowers cannot; Clearfield sunflowers can tolerate being treated with imazamox (Beyond). The result of spraying Express herbicide on Clearfield sunflowers was yellowing plants that were severely stunted (Figure 1).
I recall writing the protocol for the study in the spring and thinking to myself, “I believe we have Express sunflowers, so I will have Express in the standard postemergence treatment.” Instead of double checking and knowing, I assumed, and the result is lost data. If I had taken the three minutes to check the sales receipt e-mail, I would have a nice dataset of weed control and sunflower yield data and a comparison of the different application timings to a standard postemergence application. While I did not lose all the data, the results may not be as meaningful to sunflower farmers. Now the results would be more dramatic if I were growing sunflowers in central South Dakota for a living and sprayed Express herbicide on Clearfield sunflowers. Regardless, losing money or data is never an easy pill to swallow when you can blame only yourself. No matter how busy you are this growing season or in the future, you should never be too busy to stop and take a few minutes to double check that everything is right before starting a job (planting, spraying, harvesting, and other field tasks).
