Thursday, May 23, 2013

Pegging Peanuts (Prostko)

Over the last few days, I have been getting quite a few phone calls about "cracking" peanuts and herbicides.  The rainy weather and warm temperatures have caused a more rapid emergence of peanuts in many fields.  Additionally, the rainy weather has prevented the timely application of residual herbicides.  Here are a few things to remember:

1) DO NOT apply Valor or Prowl to peanut fields that are cracking.  The risk of injury from these herbicides is significantly increased at this stage of growth.  Growers in this situation who intended to use Valor + Prowl (or Sonalan) need to re-adjust their herbicide programs.
2) My suggestion would be to wait a few days until the peanuts fully emerge, then apply a combination of Gramoxone SL (12 oz/A) + Storm (16 oz/A) + Dual Magnum (16 oz/A).  Yes, this combination will be very "hot" but the peanuts should recover (Figure 1).
3) In my research program, I have been very successful at controlling pigweed without Valor using a Dual-based program.  An additional application of Dual (16 oz/A) should be applied in combination with either Cadre (4 oz/A) or Cobra (12 oz/A) approximately 14-21 days after the initial Gramoxone treatment. (Figure 2).
4) When Dual is included in any POST herbicide mixture used on peanuts, additional surfactant/crop oil is NOT needed.

Figure 1.  Peanut injury caused by Gramoxone + Storm + Dual Magnum - 2 DAT.


Figure 2.  Weed control in peanuts with a Dual-based herbicide program.
 







Tuesday, May 7, 2013

Roundup/Atrazine Tank-Mix Problems (Prostko)

Over the last few days, I have been bombarded with questions regarding problems with Roundup + Atrazine tank-mixtures.  Some folks have observed foaming problems while others have observed sludge/precipitate problems.  Most of the complaints I have received have revolved around the use of Roundup PowerMax and Roundup WeatherMax.  I am not really sure what is going on since I have not experienced any problems this year with my own tank-mixtures (Roundup WeatherMax + Aatrex).   I do know that Atrazine can be a difficult formulation to handle since it goes directly to the bottom of the spray tank when dumped into water.  Thus, aggressive agitation with any flowable herbicide formulation is important.  After scouring the world for some help with this problem, I came across the following publication from Monsanto which might be of use to your growers: