Two racemic and two enantiomeric pairs of new δ-hydroxy-γ-lactones based on the p-menthane system were prepared from racemic and optically active cis- and trans-piperitols. The Johnson-Claisen rearrangement of the piperitols, epoxidation of the γδ-unsaturated esters, and acidic lactonization of the epoxy esters were described. The structures of the compounds were confirmed spectroscopically. Th...

After comparing the persistence of four marking techniques, a mark–release–resight study was performed to characterize mid-season movement of the Colorado potato beetle [Leptinotarsa decemlineata (Say); Col., Chrysomelidae] simultaneously in a fallow and in a wheat field. Isolated patches of potatoes were installed in a random spatial arrangement on both fields similarly. Overwintered beetles w...

BACKGROUND Dose-response relationships for antifeedant effects of H. lupulus extracts against larvae and adults of the Colorado potato beetle (CPB) were determined in laboratory conditions. The larval and adult beetles were fed on potato leaflets treated with H. lupulus extract ranging from 0.4 to 40 mg mL(-1) in a no-choice situation. Their feeding behavior was recorded, and larval growth and ...

Studies on the feeding deterrent activity of some natural, cyclic terpenes (myrcene, (+)-3-carene, (+)-limonene, (±)-camphene), synthetic alkenes (2-methyl-1-pentene, 2,4,4-trimethyl-1-pentene, 1-methylcyclohexene, 1-tetradecene) and their derivatives α-methylenelactones in choice and no-choice tests against Colorado potato beetle with potato, Solanum tuberosum L. leaf discs as consuming food w...