Managing Corn, Cotton And Soybean Replant

JACKSON, TENN.

   We had quite a bit of cotton planted, some late corn planted and a start to soybean planting the week of May 13th that was abruptly cut short by 3 plus inches of rain and yet another cold spell on May 20. This caused quite a bit of replanting in all three crops this week particularly in cotton and soybean. The question arises about the best way to remove the partial sickly stand before the new planting emerges.

   In corn a combination of Gramoxone plus a PSII inhibitor (atrazine, simazine, diuron) will typically control the old stand. Please be advised that if the old corn stand is 3 leaf or more then go with the high rate of Gramoxone to get the best results.

   In cotton probably the best way to go is a low rate of Gramoxone on the old stand. Please note that if the old plants are over 2lf then go with a higher rate of Gramoxone.

   Gramoxone is also a good fit to remove a poor soybean stand as well. One thing to note on soybean, is that more fields are being treated with metribuzin this spring than in many years. Varietal tolerance or more precisely lack thereof has been a cause for some of our poor soybean stands. In a number of cases the soybean variety in the problem field was on the “Severe Injury or Ended in Death” categories on the University of Arkansas 2012 Metribuzin Screen.

   I highly recommend that before soybeans are planted or replanted in a field treated with metribuzin that the variety be checked against the U of A metribuzin screen. If your variety is in those last two categories, of Severe Injury or Ended in Death, either change the variety or go with a non-metribuzin pre program. Δ

DR. LARRY STECKEL: Extension Weed Specialist, University of Tennessee