6.0339.01 Field Testing of dsRNA Formulations for Controlling ALB-Year3

Double-stranded RNA is an environmentally friendly and target-specific pest control method. It is well in coleopteran insects, and commercial products targeting corn rootworm and Colorado potato beetle are registered in the USA and other countries. This can be an effective alternative to the currently registered insecticides and has the potential to integrate with natural enemies for effective eradication of coleopteran invasive pests, such as the Asian longhorn beetle (ALB), the emerald ash borer and other invasive pests that destroy trees. We have identified double-stranded RNA targeting gene coding for inhibitor of apoptosis (dsIAP) in ALB that triggers efficient RNAi and induces mortality. We have developed methods to produce dsRNA in bacteria and showed their efficacy in killing ALB in laboratory bioassays. We have also developed methods for producing large quantities of dsIAP sufficient for field testing this product. Preparation of dsRNA and testing in the laboratory and field are in progress for the first-year trial. This proposal requests second-year funding for field testing of this product to control ALB in the areas of South Carolina with current ALB infestation. Results from the first year of field testing will be used to modify methods for the preparation and testing of dsRNA in the laboratory and field. dsIAP and dsGFP (control dsRNA) will be produced to inject six trees each three times during next summer. Laboratory bioassays will test the dsRNA produced before field testing. The dsIAP and dsGFP will be injected into trees selected based on their ALB-infestation ratings conducted by state and federal regulatory personnel. ALB infestation between treated and untreated trees will be compared. Six trees will be used as control trees and injected with dsGFP. Six trees will receive dsIAP solution via trunk injection. Trees will be treated first in late June when the smallest larvae still feed on phloem. Two more injections of dsRNA will be given in July and August, with three total injections. Trees will be destructively harvested in September to determine the extent of damage (galleries), and the number of ALB larvae that survived the treatment. Successful completion of the proposed research will provide methods to manage ALB in infested areas.