Use of Prescribed Burning in Seed Production Areas to Control Red Pine Cone Beetle 13

Abstract

The red pine cone beetle, Conophthorus resinosae Hopkins, is the most common of 3 insects that destroy whole cones and reduce yields in seed production areas (SPAs) of red pine, Pinus resinosa Ail. Adult beetles are on the ground for overwintering from ca. Oct. 22–ca. May 10. After low-intensity burning of naturally accumulated fuels on 0.2-ha plots gave promising adult kills, six 0.7- to 21-ha SPAs were treated by backfire or strip-head fire burning in Minnesota, Wisconsin, and Michigan. Conophthorus infestation was greatly reduced in burned SPAs 4 ha and larger, and cones free of all cone destroyers were significantly increased in 4 SPAs by 11–45%. Combined infestation by the red pine cone moth, Eucosma monitorana Heinrich, and the red pine cone worm, Dioryctria disclusa Heinrich, went up or down after treatment depending on several factors. Adverse Eucosma-Dioryctria infestation behavior was minimized when SPAs with heavy cone crops were treated. Burning areas of sufficient size in heavy crop years the fall or spring before harvest seems a promising way to protect SPA crops from cone destroying insects.