Previous KSC support has allowed identification of resistance to soybean stem borer in soybean PI165673 (Niide et al. 2012). This resistance is inherited as a quantitative (multiple gene) trait, making development of molecular markers to track these genes more difficult. Nevertheless, experiments are ongoing to obtain markers that can help move this resistance into Kansas cultivars adapted to Kansas growing conditions and serve as a potential stem borer management tool (Aguirre-Rojas 2013). Lina Aguirre Rojas, a PhD student has refocused research efforts on Objective 1 of this proposal. She has established a soybean stem borer laboratory colony that now supply stem borer larvae on a rear round basis for RNAi-based gene silencing experiments. Alice Harris, a PhD graduate on the project, completed field experiments to understand adult soybean stem borer movement and colonization patterns in soybean. Results to date indicate that adult stem borer colonization patterns vary between fields and through time. These efforts will be expanded in the proposed objective 2 to further develop site-specific pest management strategies that mitigate losses due to borers. The KSRE Soybean Insect Management Guide (MF743), Kansas Soybean Management Guide (MF3154), and Soybean Production Handbook (C449) have been updated annually since the project began.

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We continue to seek workable solutions to reduce yield losses from the current major soybean insect pests in Kansas: the soybean stem borer, which causes stem lodging; and the soybean pod worm, which feeds on leaves and pods. Insecticides and conventional genes for insect resistance are not feasible for borer control, so we are continuing to develop a transgenic technique that kills larvae. Many factors affect the efficacy of insecticides that control soybean pod borer. Experiments continue to determine factors that promote the severity of podworm damage in the field ignorer to avoid yield losses.