The preplant burndown interval for 2,4-D and dicamba are 45 days prior to planting peanuts. Some research suggests that this interval is very conservative. None-the-less, this is the label and needs to be followed. Peanut seed is very expensive and replanting would take much of the profit out of production, especially at our anticipated cost of production and contract prices.  But these auxin materials can really help us on problematic weeds like primrose, marestail (horseweed), dock, and dog fennel and many of the summer weeds that have emerged. For a May 20 planting date, we are still in good shape for application of the auxin products but not for earlier plantings.  A one-two punch of glyphosate and paraquat can work relatively well if you find that the interval is too close to planting. If you think you have a significant number of glyphosate-resistant weeds, applying paraquat now and the following up with more paraquat can be effective.  The one-two punch of glyphosate then paraquat OR paraquat then paraquat are less effective on many weeds compared with a well-timed application of glyphosate plus an auxin herbicide followed by paraquat. But if you get too close to planting you may have to go with the less effective but hopefully adequate one-two punch without residual herbicide.

This morning I talked with someone about this and fortunately they had a cover crop that could be killed easily with glyphosate. They also had very few weeds present because of the cover crop and this opened the door for using paraquat. There was much less pressure on paraquat to perform (and glyphosate) because of the cover crop.  As we continue to deal with herbicide resistant weeds in our conservation tillage production systems, the role of cover crops in reducing the winter weeds we have to deal with will become increasingly important.