Daikon Radishes seeded in September are extremely large and would have typically winter killed by now, however, that is not the case this year. Terminating these radishes as soon as possible is recommended. Methods for terminating these radishes are listed below. These are current recommendations at this time and may change as things progress.
Chemical Termination Ahead of Early Planted Corn
For fields that will be planted to corn and are ready for the whole cover crop mixture to be burned down, the following mixture has worked well in the past.
32-40 oz/A Roundup + 1.5 oz Sharpen + MSO 1% v/v
If oats are a part of the cover crop mix, I would add 2 oz/A of a 3lb clethodim material. Stay at 2oz or below for a 3lb clethodim or the pre-plant interval to corn will increase to 30 days.
Termination Ahead of Cotton, Soybeans, and Late Planted Corn
Mechanical-Phillips Harrow and Kelly Diamond
A couple of farmers have implemented mechanical termination of their cover crop radishes before the rain set in. A Phillips Harrow and Kelly Diamond were used at these locations. These tools allow for large radishes to be broken off at the soil surface while causing minimal disturbance to grass cover crops that are in the mix. The Phillips harrow caused the least disturbance to the soil and grass cover crops.
The Kelly Diamond was more aggressive but chopped the radishes into smaller pieces-which will cause them to break-down faster. Both of these implements will leave enough grass cover crop that will need to be burned down ahead of planting. I realize with the recent excessive rainfall, this is a challenge, but assuming a mid-April to May planting date, there is still time to do this.
Chemical Termination
For fields going to cotton, soybeans, and late planted corn:
A 4lb dicamba (Clarity, Sterling Blue, Strut) + MSO 1% v/v has worked well. (See label for rates).
A follow up application will need to be made no more than 30 days before planting to kill the remaining cover crop and any radishes that remain. This applies for both the mechanical and chemical termination scenarios.
Recommendations in this newsletter are based off of on-farm herbicide plots in the past and the recent herbicide trial for cover crop termination listed below. Please contact me with any questions or comments.
