Crops injured by off-target herbicides have been too numerous for this early in the year! The most frequent problem has been corn injured by clethodim. There have been more reports and observations of this in the past 3 weeks than I can recall cumulative the past 20 years.
In my opinion, there are three reasons. First, with glyphosate no longer working on 5 grass species, clethodim is now used like never before as the “go to” for burndown. Second, with all the frequent rain there have been few days to spray causing applicators to rush. This in turn leads to higher probability of poor sprayer clean out and applications in less than ideal conditions. Third, small corn is highly susceptible to clethodim and it takes very little exposure to kill corn (Picture 1). It takes even less to cause bleaching and malformed whorls. Corn with these symptoms often will not die but may not produce an ear (Picture 2).
TDA has also gotten numerous complaints about 2,4-D drift. Most of this has been drift from pasture applications or burndowns.
Finally, a few dicamba drift issues have just recently been reported. The soybeans I have witnessed showing dicamba injury apparently were from burndown applications nearby.
I bring all this up to note that we are now in June. This is the most difficult month to keep herbicides in the targeted field as not only can they depart with wind but also through volatility with the higher temperatures this month.
Judging from the issues in May, we clearly need to up our game with respect to stewarding herbicide applications so the correct herbicide goes on the correct field. Remember the fundamentals of good herbicide stewardship: Wind speed, wind direction, applications with drift reduction agents added, sprayer boom height within 24” of the crop, etc.
Most importantly, use herbicides LABELED for use on the particular crop in the field. Only use Enlist One in Enlist crops. Never use the ester formulation of 2,4-D on pastures in the summer (Ester before Easter).
Finally, dicamba no longer has a label to be applied over Xtend crops and should not be used. Fortunately, Liberty Ultra in our research and also in fields I have walked has performed much better on pigweed so far this year than I would have anticipated. That new formulation looks to be providing more consistent Palmer amaranth control across various environmental conditions than the older 280 formulations.
