Vip3A is a novel insecticidal protein from a new class of insecticidal toxins produced by the bacterium Bacillus thuringiensis. It is expressed in Syngenta's transgenic VipCot™ cotton varieties and provides excellent control of Helicoverpa zea (CBW), good control of Heliothis virescens (TBW) and has activity against a broad range of secondary Lepidopteran pests of cotton. This novel protein is entirely distinct from the Cry -endotoxins that are also produced by B. thuringiensis and that are expressed in all other commercialised cotton varieties. Extensive in vivo and in vitro studies have shown a complete lack of cross-resistance between Vip3A and the Cry toxins, and the benefits and opportunities afforded by this are very significant. These new Vip3A-expressing cotton varieties conform with and fit well into the existing high dose + refuge approach to IRM for cotton insect pests. Moreover, a stacked variety expressing both Vip3A and Cry1Ab will provide a product with exceptional IRM properties, and work is underway to define the optimum strategy to support this product. Detailed modelling studies have been undertaken to examine the impact of this novelty. These studies indicate that not only is resistance to Vip3A in the Cotton bollworm Helicoverpa zea unlikely to occur with 15 years, but that the introduction of Vip3A expressing cotton varieties expressing Vip3A delays the time to resistance to Cry toxins in this species. Similar studies with the Tobacco budworm, Heliothis virescens and with the stacked variety are in progress.