Field Evaluation of Pheromone-Baited Trap Trees to Control Elm Bark Beetles 1 , Vectors of Dutch Elm Disease 2

Abstract

Over 250 diseased or unwanted elm trees ( Ulmus americana ) were killed with the herbicides cacodylic acid (Silvisar 510®) or MSMA (Silvisar 550®), applied either to axe-frills or by pressure injection. Elms thus poisoned and baited with the pheromone “multilure,” were mass-attacked by elm bark beetles but more than 87% of the potential brood was effectively eliminated. A decline in the Dutch elm disease rate accompanied brood elimination. We suggest that this trap tree technique will make a positive contribution to Dutch elm disease control programs by enhancing existing sanitation procedures and allowing tree removal to proceed in an orderly manner, rather than on the urgent schedule now necessary to prevent new infections vectored by emerging beetles.