GOSHEN, Ind. — As soybean growers are aware, much of the buzz this winter was about dicamba herbicide. Special training was offered to applicators who planned to use dicamba on their soybeans. It was hoped that all the extra effort would help to minimize drift, not only with dicamba, but with all herbicide products in general.
According to an article in the recent addition of the Purdue Pest and Crop Newsletter by Purdue Weed Specialists Bill Johnson and Joe Ikley, the Office of the Indiana State Chemist has indicated that the overall number of drift complaints (all herbicides), and complaints related to dicamba are tracking ahead of last year’s pace. As of Friday, July 6th, OISC had 135 drift complaints with 50 suspected to be related to dicamba. Last year on this date, OISC had 111 complaints, with 26 dicamba suspects.
Locally, I am aware of two possible cases of drift related to dicamba, but I am not sure if the cases were included in the OISC statistics.
Given that almost all the soybeans in the state now are past the R1 stage (first flowers), and that the dicamba label states it cannot be used past that stage of growth, it could be assumed that dicamba applications in Indiana should have ceased. However, with the number of weedy fields due to so much rainfall in the area, I suspect spraying will continue despite the fact that these applications are beyond the cutoff on the label.
For those of you that came to the winter training, remember that it takes 14 to 21 days for injury symptoms to show up. So, there could be continued development of symptoms on sensitive vegetation like non-extend beans and other sensitive species. It is likely the number of complaints (official and unofficial) and samples submitted to our Plant Pest Diagnostic Lab will continue to roll in for at least a couple of more weeks.
The University of Missouri weed science program is surveying soybean and cotton producing states every two weeks or so for updates on number of drift complaints filed with regulatory agencies, and estimates of dicamba damage to soybeans and other sensitive species. To view the latest report, see this website: https://ipm.missouri.edu/IPCM/2018/6/dicambaInjuryUpdate/
If you are interested in contributing data to this report, our Purdue Extension ANR Educators are being surveyed every couple of weeks for information from their counties. If you contact my office, I will relay the information to Purdue’s Weed Science department.
However, if you have vegetation (soybean or other sensitive species) that has been damaged by herbicides and you want to file an official complaint, then you need to contact the Office of the Indiana State Chemist. This needs to be done within 30 days of the incident.
Purdue University is an affirmative action, equal access/equal opportunity institution.
— Jeff Burbrink, Extension Educator, Purdue Extension Elkhart County
For more news from Indiana, click here.