Assessing the efficacy of <i>Bt</i> maize MON 95379 expressing Cry1B.868 and Cry1Da_7 in different hybrids as a tool to manage early season pests in Brazil

The intensification of agriculture in tropical landscapes has posed significant challenges to pest management programs worldwide. While primary pests have been the focus of biotechnological advancements in crop design, the impact on early season pests often has been overlooked. Consequently, outbreaks of these pests have been reported globally. The Bt maize event MON 95379 expressing Cry1B.868 and Cry1Da_7 was approved for commercial use in Brazil in 2020. Although it has high efficacy against primary maize lepidopteran pests, there is no information on its effects on early season pests. In this context, our purpose was to investigate MON 95379 (Cry1B.868 + Cry1Da_7) levels of protection across tropical maize germplasm against Elasmopalpus lignosellus (Zeller) (Lepidoptera: Pyralidae) and Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae). Bt hybrids expressing Cry1B.868 + Cry1Da_7, Cry1A.105 + Cry2Ab2 + Cry3Bb1, and Cry1A.105 + Cry2Ab2 + Vip3Aa + Cry3Bb1 + RNAi exhibited no symptoms of plant mortality after 15 d post-infestation by E. lignosellus, a statistically significant improvement compared to the average observed in a non-Bt hybrid (∼85%). Similarly, low levels of plant mortality (<10%) were recorded across all Bt hybrids during the same evaluation for A. ipsilon, while the non-Bt hybrid showed an average plant mortality rate of 60%. These findings indicate that MON 95379 (Cry1B.868 + Cry1Da_7) may fit as an effective tool for managing early season pests in maize.