Protecting Ponderosa Pine from Dendroctonus with VerbPlus Repel

This SBIR proposal targets the western pine beetle (WPB) Dendroctonus brevicomis LeConte (Coleoptera: Curculionidae, Scolytinae), the most destructive insect pest of ponderosa pine, Pinus ponderosa Douglas ex Lawson, in much of western North America. This insect causes high levels of tree mortality, inflicting millions of dollars in losses each year. One million or more trees, equivalent to more than 1 billion board feet of timber, may be killed each year as the result of an outbreak. Such extensive tree mortality may deplete timber supplies, adversely affect levels and distributions of stocking, disrupt management planning and operations, and increase the potential for forest fires by adding an abundance of dead, dry timber to available fuels. Current tactics for managing WPB infestations are very limited, primarily consisting of tree removals (thinning) and preventative single tree treatments using large quantities of conventional insecticides. We propose to explore the chemical ecology of WPB in order to develop more effective, environmentally-safe, and widely-applicable management tools to protect ponderosa pine trees. Researchers at ISCA Technologies (Riverside, CA), along with collaborators from the USDA Forest Service, have been studying the chemical ecology of WPB for the past decade, and have discovered that treating ponderosa trees with a blend of nonhost angiosperm volatiles (NAVs), together with the antiaggregation pheromone verbenone, effectively disrupts orientation and host-finding behavior, and disables semiochemical coordination of mass attacks, thereby protecting the ponderosa host tree from infestation. Our proposed management strategy focuses on single tree protection and local applications of a long-lasting formulation containing non-host volatile semiochemicals and verbenone. VerbPlus Repel will be formulated to release these NAV semiochemicals over a sustained interval of time (ideally, up to five months) at levels that disrupt the aggregation behavior of WPB, providing long-term protection for individual pine trees or forest stands. The final VerbPlus Repel formulation will be an organic, flowable substrate that will allow for manual and ground-based mechanical applications directly to trees, using conventional off-the-shelf equipment. The successful development of VerbPlus Repel to manage WPB will create opportunities for expanding the use of NAV semiochemicals into management programs for other important bark beetle species, increasing the economic and societal benefits resulting from this USDA NIFA SBIR project.