Host preferences of the leafhopperScaphoideus titanus, vector of “flavescence dorée” phytoplasma

Abstract

The spread of “flavescence doree” (FD) phytoplasma among grapevines is made by the leafhopper Scaphoideus titanus (Hemiptera: Cicadellidae). Laboratory choice tests were performed to better understand insect vector preferences. The host preferences of nymphs and adults were compared between an experimental host plant, broadbean, and its natural host plant, grapevine, and between healthy and FD-infected plants. Grapevine was preferred to broadbean by nymphs and adults, but this preference was influenced by feeding experience. The presence of FD phytoplasma in plants made FD-infected grapevines more attractive than the healthy ones to both instar stages tested, while the preference for infected broadbean over healthy ones was only observed in adults. Plant yellowing due to the phytoplasma may increase the attractiveness of FD-infected plants. The experimental results showed that S. titanus was more attracted to yellow cues than to green, blue, or red ones. The attractiveness of FD-infected grapevines to the vector could be an efficient way to enhance disease spreading by increasing the proportion of infective vectors in the population.