The Effect of α-Methylenelactone Group on the Feeding Deterrent Activity of Natural and Synthetic Alkenes Against Colorado Potato Beetle, Leptinotarsa decemlineata Say

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 were carried out. Deterrent indexes determined in the tests show that the strongest antifeedant to larvae and adults of Leptinotarsa decemlineata was α-methylenelactone obtained from 2,4,4-trimethyl-1-pentene. The structure modification of (+)-3-carene and (±)-camphene via introduction of α-methylenelactone moiety increased their deterrent activity, especially against larvae. Other starting alkenes and α-methylenelactones obtained from them were weak deterrents to both developmental stages of L. decemlineata.