Location: Plant Genetics Research
2013 Annual Report
This work is related to Objective 1 of the parent project: “Develop lines of the western corn rootworm resistant to transgenic corn and investigate the biology, pest/host interactions, and fitness costs of resistant and control colonies as they relate to resistance management and rootworm biology” and addresses research conducted under NP304 "Crop Protection and Quarantine" Component 1: Protection of Agricultural and Horticultural Crops.
Seed mix “refuges” have recently been registered for commercial sale and are likely to become the dominant tactic to delay the evolution of resistance of insect pests to Bt corn. In seed mix refuges though, insect movement from plant to plant sometimes speeds the development of resistance. To understand the role of western corn rootworm larval movement in a seed mix scenario, a series of treatment combinations were evaluated in the field (all Bt, all isoline, isoline surrounded by Bt, and Bt surrounded by isoline corn). Each combination of Bt and isoline corn had two types of rootworm infestations. Although Bt corn performed quite well in nearly all planting and infestation combinations, when surrounded by two highly damaged isoline plants, damage to Bt plants increased significantly due to larval movement from nearby isoline plants. This study was performed using two Bt lines registered for commercialization by the Environmental Protection Agency (EPA).