First insights into the influence of aster yellows phytoplasmas on the behaviour of the leafhopper Mgenia fuscovaria

Phytoplasmas can alter the behaviour of their insect vectors by modifying host plant and insect characteristics. In a dualchoice cage experiment, field-collected adult Mgenia fuscovaria were preferentially attracted by grapevine (cultivar Colombard) branches infected with aster yellows phytoplasma compared with uninfected branches. The influence of colour as a visual stimulus for M. fuscovaria was determined in a field trial. More adults were trapped on yellow and lime green than red, blue, white, and dark grey sticky colour cards. Within the green-yellow wavelength range more adults were attracted by the colour with the highest peak reflectance. Yellow is suitable for monitoring M. fuscovaria.