EVALUATION OF MONOSODIUM METHANE ARSENATE FOR THE SUPPRESSION OF NATIVE ELM BARK BEETLES, HYLURGOPINUS RUFIPES (EICHHOFF) (COLEOPTERA, SCOLYTIDAE)

The native elm bark beetle, Hylurgopinus rufipes (Eichhoff), is the ma jor vector of Dutch elm disease, Ophiostoma ulmi (Buisman) Nannf., in Manitoba. The herbicide Glowon(TM), monosodium methane arsenate (MSMA) , was applied to a chainsaw cut in American elm, Ulmus americana L., t ree stems to determine if the treated elms would become effective trap trees for H. rufipes. Three treatments were compared: treated with he rbicide and girdled, girdled, and control. All herbicide-treated elms died within 18 days after application. Significantly higher numbers (P < 0.01) of native elm bark beetles were attracted to the herbicided e lms, compared with the other treatments. Beetles bred only in the elms treated with herbicide. Of the total brood galleries constructed, 72% had no egg hatch while the remaining 28% had larval tunnels. Progeny adults emerged from less than 1% of the larval tunnels. MSMA applicati on could supplement the Dutch elm disease management program in Manito ba.