49th TWC, Tob. Work. Conf., 2020, abstr. 56

Organic suckercides - the unsuccessful search for an alternative to fatty alcohol

North Carolina State University, Raleigh, NC USA

Organically derived fatty alcohol products are useful for the control of tobacco axillary buds (suckers) and are greatly needed by commercial tobacco farmers. Recently, USDA-National Organic Program approval of these products has been scrutinized, leaving farmers, certifying agencies, and tobacco buyers with questions about the efficacy and injury potential of alternative products. The objective of this research was to evaluate a variety of materials that might be used for chemical sucker control. Materials investigated included pelargonic acid, vegetable oil, canola oil, and peppermint + spearmint oil using two different application methods: a standard 3-nozzle boom or a dropline. Fatty alcohol was included for comparison and evaluated using both application methods. Chemical injury was minimal following each 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 following the dropline application was still greater than that resulting from other treatment combinations. Sucker control was acceptable with pelargonic acid (83 to 98%) and was similar to that resulting from fatty alcohol (99-100%). Sucker control was <40% among all other treatments, with peppermint + spearmint oil (32 to 34%) providing better efficacy than canola (9 to 15%) or vegetable oil (-3 to 7%). Cured leaf yield, quality, and value were likewise greatest in fatty alcohol treatments due to maximized sucker control and minimized chemical injury. Treatments containing the alternative products resulted in lower post-harvest measurements due to extreme injury (pelargonic acid) or poor sucker control. Producers are encouraged to utilize fatty alcohol until the alternative products can be re-formulated and re-evaluated. (Reprinted with permission)