Organic Sucker Control: Screening Different Active Ingredients for Commercial Application

Abstract

Organically derived fatty alcohol is useful for the control of tobacco axillary buds (suckers) and is greatly needed by commercial organic tobacco farmers. Recently, its approval by the U.S. Department of Agriculture (USDA)-National Organic Program has been scrutinized. The objective of this research was to evaluate the suggested alternatives: pelargonic acid, vegetable oil, canola oil, and peppermint + spearmint oil using two different application methods, a standard 3-nozzle boom or a dropline. Chemical injury was not observed within any treatment except for those containing pelargonic acid. Injury was greatest when applied with the 3-nozzle boom and was reduced by nearly 50% with the dropline; however, injury after the dropline application was 2.5 to 7 times greater than any other treatment. Despite significant injury, sucker control was acceptable with pelargonic acid (≈90%) and was similar to that resulting from fatty alcohol (99–100%). Sucker control was <40% among all other treatments, with peppermint + spearmint oil providing better efficacy than canola (10 to 15%) or vegetable oil (−1 to −10%). Cured leaf yield, quality, and value were likewise greatest in fatty alcohol treatments because of maximized sucker control and minimized chemical injury. Producers are encouraged to utilize fatty alcohol until the alternative products can be reformulated and re-evaluated.