Walked a few fields and gotten more calls on pre emergence herbicide injury to cotton and soybean. This does not come as a surprise given the “Blackberry Winter” we had last week coupled with heavy rain.
Cotton and soybean planted the week of May 5th were just trying to emerge last week in the very cold and wet soil conditions. We were going to have some struggling cotton and soybean stands with that weather even with no herbicide present. With the young seedlings emerging with activated herbicides through cold and wet soil conditions magnifies the problem.
In cotton the calls have come from fields treated with Cotoran, Caparol, Cotoran plus Caparol and Reflex. In other words the main pre applied herbicides. In these fields burn from the herbicide appears to be helping seedling diseases to dampen off some cotton seedlings. This is more typically found in low areas of fields. In the fields I have walked it appears the cotton that is living now will likely go on to make a stand. The warm temperatures this week are just what was needed. So far even with these problems, replant appears to be less than 15% which is a huge improvement from last year when it was common to replant what had already been replanted.
In soybeans the calls have been fewer and have mostly come from fields treated with Valor based herbicides (Valor, Envive, Fierce etc.). A couple of these were on tilled soil where the heavy rain splashed herbicide treated soil up on the terminal. In some cases the terminals have been burned off. These soybean fields look very ugly now. However my experience has been that soybeans with Valor splash injury typically recover. When checking fields with this type injury, examine the terminal as well as the axillary buds. If regrowth is starting at any of these growing points the soybeans should recover.
We have also gotten a couple reports on injury with other pre applied herbicides like Authority based herbicides and Sharpen. Again if the stand is there I would expect these fields to recover. In our research this spring as well as last spring with any given pre we saw some soybean injury. We also had good Palmer control. Where the soybeans had no injury was where no pre was applied and the treatment was awash in pigweed.
Unfortunately, the days of glyphosate controlling all the weeds are gone and crop stress from pre applied herbicides is a fact of life. Wet and cold conditions during emergence can compound the problem. However, these pre applied herbicides are the key component to Palmer amaranth management. In other words the downside of early season crop injury is more than made up for by their benefit of more consistent Palmer control in this year’s crop as well as curtailing future herbicide resistance.
