Mixture of Synthetic Herbivore-induced Plant Volatiles Attracts More Stethorus punctum picipes (Casey) (Coleoptera: Coccinellidae) than a Single Volatile

We compared the attractiveness of a mixture of cis-3-hexen-1-ol, cis-3-hexenyl acetate, and methyl salicylate (MeSA), and of each of these compounds singly, to a predacious ladybird beetle, Stethorus punctum picipes (Casey), to make it clear whether mixture of several volatiles may attract more natural enemies at different spatial scales. In an olfactometer experiment, S. p. picipes females were attracted to the volatile mixture, but not to single volatiles. Male S. p. picipes were not attracted to the mixture. In a small-scale open-field test using sticky cards, S. p. picipes were attracted to the volatile mixture and to MeSA alone. In a vineyard trapping test, significantly more S. p. picipes were trapped on sticky cards baited with a mixture of volatiles than on single-volatile-baited cards.