Differential response of male and female emerald ash borers (Col., Buprestidae) to (Z)-3-hexenol and manuka oil

We conducted two trapping experiments in green ash plantations in Ontario, Canada to compare the response of the emerald ash borer (EAB), Agrilus planipennis, to (Z)-3-hexenol (Z3-6:OH) and manuka oil. In the first experiment, Z3-6:OH (7.6 mg/day) in purple prism traps hung 1.5 m above ground caught significantly more EAB than the unbaited controls, with male catches significantly greater than female catches at two locations. Manuka oil (50 mg/day) attracted equal numbers of males and females but they were significantly greater than the controls at only one location. Adding (Z)-3-hexenal or (Z)-3-hexenyl acetate in binary or ternary combinations with Z3-6:OH did not enhance trap catch. In the second experiment, Z3-6:OH released at two rates (7.6 or 80 mg/day) in light green prism traps placed in the ash canopy also caught significantly more males than females and more males than the unbaited controls or manuka oil-baited traps. Manuka oil had no significant effect on catches relative to the controls. Combining Z3-6:OH with manuka oil did not enhance catches of EAB. We conclude that there was a strong male-biased EAB response to Z3-6:OH lures, whereas manuka oil, when effective, attracted both sexes equally. Z3-6:OH in light green prism traps in the canopy is an effective lure for EAB, particularly for males.