A few things to consider as we head into July:
1) Cobra or Ultra Blazer applications should be avoided if possible when the peanut plants are in the R5 (beginning seed) to R6 (full seed) stage of growth (Figure 1). Results from a 9 location study conducted in 2005-2006 indicated that Cobra applied at this time could cause a significant peanut yield loss (~5%).
Figure 1. Peanut Stages of Growth.
2) Nearly all 2,4-DB labels limit the official number of applications that can be made in peanut to 2. Check out Figure 2 for a list of how much and when 2,4-DB can be applied according to current labels.
Figure 2. Summary of 2,4-DB labels for use in peanuts.
3) On more than 1 occasion this year, growers have accidently applied 2,4-D amine rather than 2,4-DB to peanut plants. Fortunately, we have a good idea what could happen to peanut yields when this occurs (not that bad depending upon rate and peanut stage of growth).
(Source – http://www.farms.com/news/peanut-weed-tips-from-dr-prostko-93812.aspx)