Location: Vegetable Crops Research
Project Number: 5090-21220-005-17-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 1, 2018
End Date: Aug 31, 2019
Objective 1- Measure declines in fitness or mortality in the Colorado potato beetle following exposures to field relevant concentrations of heavy metals and associated metal-based fungicides. Objective 2- Determine the genetic responses of selected populations of Colorado potato beetle to field relevant, metal-containing agrochemicals using the insect transcriptome. Objective 3- Characterize the potential for synergy between metal-based agro-chemicals and other fungicides, to impart cross-resistance on selected populations of the Colorado potato beetle.
Objective 1. Using a known imidacloprid-susceptible population of Colorado potato beetle (CPB) as a model, we will evaluatethe impactsof soluble heavy metals (Cu, Fe, Mn, Sn, Zn), as well as formulated heavy-metal containing fungicide formulations, on insect fitness, development time and potentially mortality. Using field relevant rates of these soluble heavy metals, and associated formulated fungicides registered in potatoes, we will investigate the physiological effects on 3 replicate sets of insects (N=18 total insects/treatment) through a feeding bioassay using dip-treated foliage. Objective 2. Using previously generated RNA sequencing databases we will determine the biological responses (and associated over-expressed genes) that heavy metals and associated fungicides induce in insects. Objective 3. A select set of replicate assays will also be conducted with imidacloprid-susceptible and resistant populations of CPB using water soluble metals together with metal-containing fungicides in combinatorial assays. From populations of beetles collected in potato fields in Maine (N=3 resistant populations) and Oregon (N=3 susceptible populations), we will further investigate genetic biomarkers for over-regulation of resistance mechanisms classified in Objective 2 in select populations where we have known history of extreme resistance (eastern US) in comparison to populations where insecticide susceptibility remains high (western US).