Host plants and seasonal presence of Dictyophara europaea in the vineyard agro-ecosystem

Abstract

Seasonal presence and host plants of Dictyophara europaea (L.), a candidate vector of phytoplasmas to grapevine, were studied in Piedmont during 2006 in different vine growing regions. Sampling consisted in net sweeping on different candidate host plants, and captures of adults with yellow sticky traps placed on grapevine. D. europaea nymphs and adults were collected on many weeds, showing how this planthopper should be considered a polyphagous species, although Amaranthus retroflexus L. and Urtica dioica L. seem to be its preferred hosts, and may also bear phytoplasmas. Larvae of Dryinidae were observed on almost 5% of collected individuals. The peak of adult presence was recorded in the middle of August, but few adults were captured on sticky traps placed on grapevine. Molecular analyses will be performed to detect the presence of phytoplasmas in captured individuals; however, given its scarce presence on grapevine, D. europaea does not seem capable to play a major role in the transmission of phytoplasmas to grapevine even if its vector ability were proved.