Wound Response of Ulmus americana I: Results of Chemical Injection in Attempts to Control Dutch Elm Disease

Abstract

Concern for injury to elms from chemical injection led to an evaluation of the impact of wounding and exposure to liquid fungicide on the wound response of Ulmus americana . Small elms were injected with thiabendazole (TBZ) plus solvent, its solvent alone, or water. The external symptoms of injury following injection were observed over a 23 month period and the internal response to injury was recorded over a 33 month period from dissection of stems during the growing and dormant seasons. Wounds with water injection had small columns of discolored wood while wounds with chemical injections had large columns of discolored wood. TBZ treatment was toxic to woody tissues and caused the largest amount of discolored tissue in trees injected in May and June. The extensive amount of discolored wood associated with injected fungicide indicated that precautions must be taken such that injections will not limit future distribution of fungicide, decrease storage and transport capacities and predispose trees to other infectious agents.