Many of the peanuts that have been planted so far are just beginning to “crack” or emerge through the soil surface. Some special considerations need to be taken to avoid causing injury when applying herbicides to peanuts at this critical time of crop growth and development.
Here are some of UGA Weed Scientist Eric Prostko’s comments on the subject:
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 Dual-based herbicide program.