Boring deterrent compounds to enhance mycoinsecticides for bark beetle control

Montana BioAgriculture Inc., MBAI, is developing fungal insect pathogens as mycoinsecticides for bark beetles. With climate change and globalization, outbreaks of both native and introduced species of bark beetles are occurring at an unprecedented scale; killing trees on millions of acres of forest and causing substantial economic loss in timber harvest and in value of both private and public forests for recreation, urban forests, and landscaping. In initial field trials, fungal pathogens isolated by MBAI from conifer habitats showed promising results against two important bark beetles, spruce beetle and pine engraver. These beetles preferentially infest and increase population in down trees then emerge to attack standing trees. Fungal pathogen spores applied to down trees, killed up to 86% of spruce beetle adult and reduced larval numbers by more than 50%. Results suggest that increased exposure of the beetles to fungal spores or more time for infection to develop could stop beetle reproduction. Treating down trees and logging slash to prevent reproduction would limit outbreaks of these beetles.MBAI previously screened natural products biochemicals and identified compounds that deter boring behavior of mountain pine beetle. Combining a fungal pathogen with a compound that delayed boring of adult beetles would both increase exposure to spores on the log and increase time for infection to develop. Objective of this proposal is to select compounds that deter boring behavior of spruce beetle and pine engraver. In phase 1 MBAI will: Screen compounds for boring deterrence of these two beetle species; Test for increased efficacy of the fungal pathogen when combined with selected boring deterrent compounds; Evaluate compatibility with fungal pathogen formulations; Evaluate solubility and application methods; and Investigate regulatory issues for selected compounds.MBAI sees a significant market for bark beetle mycoinsecticides in forestry where there are no effective biological insecticides and where the use of the few approved chemical insecticides is limited by safety and environmental concerns. The combination of naturally occurring fungal insect pathogens with boring deterrents to create effective, safe and environmentally benign mycoinsecticides would provide forest managers with a new tool for managing bark beetles. Evaluating boring deterrents against species in two different genera, Dendroctonus and Ips would also provide valuable insights into an underexplored aspect of bark beetle behavior; insights which could be very valuable in developing safe and effective biological control for many damaging species of bark and wood boring beetles.