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.
We planted 280 acres of Stoneville 4145 LLBG2 cotton on 5/19 & 5/20. It rained nearly 4″ on 5/21. We evaluated the stand on 5/27 and decided to re-plant. We re-planted all of those Liberty Link acres with two Glytol varieties – Stoneville 4946 & Fibermax 1944. Our plan is tank-mix RUPM with acephate when we spray for thrips to clean-up the insects and the first planting cotton stragglers.
How much rain does it take to dilute Caparol applied at 1 qt/acre as a pre-emerge for cotton to where it will not injure soybeans planted in the same field?
Richard
Caparol is one of the least soluble PSII inhibitors. My first thought is to replant an early season cotton variety if you can plant next week.
Larry
Does the metribuzin recommendation apply if it was applied to wheat back in Feb/early March? Where can I go to check for varieties that aren’t listed in the U of A study? Specifically Asgrow 3832 & 3931. Check with Monsanto rep? Lastly, we were dumped with 4+ inches of rain over the weekend on freshly replanted corn. In the event it doesn’t survive, would you roll the dice and replant corn again on irrigated, strong bottom ground? A couple variables to this situation: insurance covered first replanting, but won’t cover a second if it fails, and some of the old stand had to be destroyed and metribuzin was used.
Shane
I would not worry about metribuzin that has been applied for more than 2 weeks with all this rain as it is played out. As far as group 3 info on metribuzin tolerance I would check with Tye Parker or Larry Garnand with Monsanto or with your retailer you purchased the seed.
I would be inclined to replant back to corn on irrigated or a strong bottom as long as the hybrid carries the BT trait. Back when I worked for Pioneer up in Southern Illinois we could often get pretty good yields with June planted corn and that was before the BT trait.
Also on later planted corn there is a good chance that leaf disease could be more of an issue particularly southern rust which blows in from the south. So be prepared to spray a fungicide….
What ever you decide….Good luck!
Larry
Do you know how much metribuzin was applied in the U of A test? I couldn’t find it in the article.
Alan
I believe they were conducted in the greenhouse. The environmental conditions were very good. The rate I think was 10 oz/A so pretty high….
Thanks
Larry