Sweet Potato Hotbed Projects 2011 Results
In 2011, the only fumigant treatment that provided adequate weed suppression was MeBr. Even though Pic was applied at very high rates under totally impermeable film (TIF), weed suppression was negligible. However, most of the weeds, with the exception of yellow nutsedge, were effectively controlled with the herbicides evaluated at each location, regardless of fumigation treatment.
Application of Devrinol or either rate of Valor significantly reduced the number of weeds as compared to not treating, with Valor having the greatest efficacy on the weeds present. Dacthal prevented most weed growth, but caused substantial crop injury and cannot be recommended for use in hotbeds even though it is a registered herbicide for sweetpotatoes. No crop phytotoxicity was seen as a result of the main plot fumigation treatments, and there were no differences in plant production between any of the treatments with the exception of Dacthal.