Differences in host-plant related chemical communication of the flea beetlesPhyllotreta cruciferaeGoeze andPh. vittulaRedtenbacher (Coleoptera, Chrysomelidae)

Abstract

Remarkable differences have been found in host-plant related chemical communication between Phyllotreta cruciferae Goeze and Ph. vittula Redtenbacher (Coleoptera, Chrysomelidae). In preliminary screenings sizeable catches of Ph. vittula were recorded in traps baited with either 3-butenyl isothiocyanate, or a quternary mixture of 2-butenyl-, phenethyl-, 3-butenyl-and butyl isothiocyanates. Later studies revealed that Ph. vittula responded better to the above isothiocyanate mixture, than to allyl isothiocyanate, while Ph. cruciferae catches were always greater in allyl isothiocyanate baited traps. Of the four isothiocyanates in the mixture, 3-butenyl isothiocyanate may predominantly be responsible for attractivity of the mixture towards Ph. vittula .As such differences in isothiocyanate preference may occur also in other flea beetle species, for practical applications more efficient, selective and sensitive baits and traps may be developed in the future based on improved knowledge of the chemical communication of flea beetles and through optimal combination of effective isothiocyanate compounds. Both Ph. cruciferae and Ph. vittula rank among the most important pest flea beetles in Europe.