Evaluation of monosodium methane arsenate for the suppression of native elm bark beetles, Hylurgopinus rufipes (Eichhoff) (Coleoptera: Scolytidae).
The native elm (Ulmus americana) pest, Hylurgopinus rufipes, is the major vector of Dutch elm disease (Ophiostoma ulmi [Ceratocystis ulmi]) in Manitoba. The herbicide Glowon, monosodium methane arsenate (MSMA), was applied to a chainsaw cut in U. americana trunks to determine whether the treated elms would become effective trap trees for H. rufipes. Three treatments were compared: treated with herbicide 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 herbicide-treated elms, 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. It is concluded that MSMA application could supplement the Dutch elm disease management program in Manitoba.