Pyrethroid insecticides for control of European elm bark beetle (Coleoptera: Scolytidae)

Commercial formulations of four pyrethroid insecticides, fluvalinate (Mavrik), permethrin (Pounce), cypermethrin (Ammo), and esfenvalerate (Asana), were 222-548 times more toxic to European elm bark beetles, Scolytus multistriatus (Marsham), than was methoxychlor. Compared with methoxychlor, all of the pyrethroids provided superior protection from twig feeding; two products, cypermethrin and esfenvalerate, killed all beetles contacting sample twigs and prevented twig feeding through an 18-wk period of bioassays after spray. The same two compounds applied to infested elm wood killed all beetles before, or shortly after, they emerged; chlorpyrifos also caused 100% mortality of beetles emerging from brood wood, but its action was not as rapid. The pyrethroids tested could increase the effectiveness of spraying elm crowns to prevent Dutch elm disease. They also could be used to eliminate elm bark beetles as they emerge from brood wood or land on treated surfaces baited with attractants. Potency and durability combined with their low risk to birds and mammals give the pyrethroids excellent potential for the control of other tree pest insects