By: Peyton Sapp, Burke County Ag Agent
I had 2 inquiries earlier this week about the potential of Cadre, when normally applied to peanuts during the growing season, to cause injury to fall planted oats. This was one issue I tackled very early on in my career here at UGA. Here are a few things for you to consider:
1) According to a recent (2018) USDA/NASS survey of pesticide use in peanut, Cadre is used on 59% of the peanut acres in Georgia.
2) The official labeled rotation restriction for oats after an application of Cadre is 18 months!
3) Field research conducted in Georgia indicated that the rotation for oats could potentially be reduced to 4 months (like other small grains) but the label was never changed (and will not be changed) due to the limited amount of oat acres planted. Oats were planted on 70,000 acres in Georgia in 2019. U.S. total planted oat acres were 2,810,000 in 2019.
4) Oats planted less than 4 months after a Cadre application could very likely be injured (Figure 1). Note that Cadre injury to oats also looks very much like phosphorus deficiency and/or cold injury so these potential problems would need to be investigated as well. We had at least 1 freeze event here in Tifton around November 13.
5) When Cadre was applied to bare-ground (a worse case scenario, i.e. 100% of Cadre reaching the soil surface and no peanut uptake/metabolism) either 5, 4, 3, 2, or 1 month(s) before oat planting, total forage yield was only significantly reduced by the 1 and 2 month timings (61.6% and 22.4% forage yield losses, respectively). Interestingly, oat grain yields were not reduced by any pre-plant application of Cadre.
6) I do not have any hard data to back this statement up but it makes sense that oat injury could be worse in short-planted fields where Cadre-treated dryland peanuts were grown.
7) Complete results of this Cadre/oat research can be obtained from the following paper:
Prostko, E.P., T.L. Grey, R.N. Morgan, and J.W. Davis. 2005. Oat (Avena sativa) response to imazapic residues. Weed Technology 19:875-878.
8) Culpepper is the small grain weed guy so he would be more than happy to walk any and all small grain fields including oats!!!!!!