SPINOSAD - A biopesticide for the control of stored-tobacco insect pests
Every year, raw tobacco and manufactured tobacco products are lost to storage pests. The cigarette beetle, Lasioderma serricorne and the tobacco moth, Ephestia elutella are the major insect pests to control. Post-harvest management of both insects is achieved through sanitation, insect monitoring, and fumigation with phosphine. However, insect resistance to phosphine and control failures have been reported, while fumigants are subject to regulation. The objective of our study was to evaluate SPINOSAD (Dow AgroSciences LLC, Indianapolis, IN), a novel insect control agent derived from the fermentation of a naturally occurring soil microorganism, Saccharopolyspora spinosa Mertz & Yao. It was first registered in the USA in 1997 and is now widely used as a field pest control agent on many crops, including tobacco. The insecticidal activity of the fermentation product (as technical spinosad, TS) against L. serricorne and E. elutella larvae was measured by diet incorporation assays. Mortality levels were determined over the whole insect life cycle. For both species, no emergence of adult insects was observed in cured tobacco sprayed with 50 ppm TS and inoculated with newly hatched larvae. These experimental results indicated that spinosad has potential for the control of both species in stored tobacco, since 100% control of both pests could be achieved at that application level.The stability of the product on cured tobacco leaves is currently being assessed and the product has already proved to be stable over a storage period of 3 months. It was shown that the original TS concentration on tobacco was maintained and that the bioinsecticidal activity against larvae was retained.