Here are some comments from Dr. Eric Prostko, Extension Weed Specialist, about the combination of Warrant and Valor for pre-emerge weed control in peanut:
“As I sit in my office watching yet another rain event (April 29), I am wondering why most GA growers seem to have a passion/obsession for using Warrant in every row crop possible. It must have something to do with the Monsanto Rewards Program. Anyway, I have been getting a lot of questions about mixing Warrant + Valor for PRE weed control in peanut. Here are a few random thoughts:
1) The combination of Valor + Warrant is a perfectly legal/labeled option for GA peanut growers.
2) Using Warrant PRE (except when planting later in May in fields with a history of tropical spiderwort/Benghal dayflower) in my opinion is a waste of its residual power. There is not a lot of evidence in peanut to suggest that Warrant + Valor is significantly better on Palmer amaranth than Valor alone (i.e. assuming starting clean with rainfall/irrigation activation).
3) Warrant is not very effective on Texas panicum. That is why I always recommend either Prowl or Sonalan in combination with Valor. You can probably count on 1 hand the number of fields in GA that do not have Texas panicum????? OK, there might actually be more than 5 fields???
4) I believe a better fit for Warrant in early planted peanut fields is to use it in combination with POST herbicides such as Gramoxone or Cadre. However, the current Warrant label prohibits the use of Warrant on peanuts that are flowering. A big mistake on Monsanto’s part which I hope will be corrected in the future.
5) Early planted peanut fields are usually subject to cooler and wetter conditions which can lead to greater injury from PRE applied residual herbicides. Although I have not yet observed this phenomenon, Valor + Warrant or Dual could be more injurious to peanut than either applied alone in the wrong situation (low vigor/germ seed, improper planting depth, heavy rainfall, high rates, etc.).
6) I have not observed any real differences between Warrant and Dual Magnum when used in a peanut weed management program. As far as I am concerned at this point, flip a coin on these two!!! FYI, Dual is more effective on yellow nutsedge than Warrant.”