Behavioural responses of larvae of Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae), to host plant volatile blends attractive to adults

Abstract

1. Orientation of second- and fourth-instar Colorado potato beetle (CPB) Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), to volatiles emitted from a solanaceous host, potato, and seven synthetic blends or three individual chemicals emitted by potato plants were investigated in laboratory bioassays. 2. Both second- and fourth-instar CPB were attracted to intact and mechanically damaged (MD) potato foliage. When offered a choice between intact and MD foliage, no preference was observed. 3. Among seven synthetic blends tested (of which six are attractive to adult CPB), second- and fourth-instar CPB were attracted only to a single three-component blend comprising (±)-linalool, methyl salicylate, and (Z)-3-hexenyl acetate. Individual compounds and two-component blends were inactive. No significant difference was noted between larval responses to the attractive synthetic blend vs. MD potato foliage. 4. Second-and fourth-instar larvae had similar thresholds for behaviour for the three-component blend (50μg source load). Female CPB were attracted to source loads 10x below the larval threshold (5 μg). Male CPB were the most sensitive life form tested with a behavioural threshold at 0.5 μg source load which was 10x and 100x below female and larval thresholds, respectively 5. This is the first report of a synthetic chemical attractant for CPB larvae. As both larval and adult CPB are attracted to a single chemical blend, the usefulness of the attractant as a component of an attracticide or 'push-pull' strategies for management of pestiferous populations is enhanced.