Comparisons of Efficiency of Two Formulations of Verbenone (4, 6, 6-trimethylbicyclo [3.1.1] hept-3-en-2-one) for Protecting Whitebark Pine, <i>Pinus albicaulis</i> (Pinales: Pinaceae) From Mountain Pine Beetle (Colopetera: Curculionidae)

Abstract Whitebark pine, Pinus albicaulis Engelm., is a subalpine tree endemic to western North America. This species provides multiple ecosystem services and suffering widespread mortality from mountain pine beetle, Dendroctonus ponderosae Hopkins. Verbenone pheromone produced as D. feed, high air concentrations of verbenone deter colonizing trees. Synthetic has been formulated into products used prevent We compared the ability pouches SPLAT Verb protect individuals small stands P. albicaulis. With individual trees in Montana, all treated survived regardless formulation rate, whereas untreated suffered 70 90% 2015 2016. In plot experiments California 2017, Oregon 2018, was applied spaced ~10 m apart, survival (12.7–23 cm DBH = diameter at 1.37 height), medium (23.1–33 DBH) large (&amp;gt;33 compared. California, where &amp;gt;80% survived, increased ~2 3% ~4 7% size. Oregon, performed similarly on trees, but had greater when with (~93%) than (~82%). Compared pouches, appears better ponderosae.