Fundação para a Ciência e a Tecnologia,
Grant/Award Number: (LA/P/0007/2020, 2020.07051.BD and UIDB/00690/2020; Horizon 2020 Framework Programme, Grant/Award Number: Grant Agreement 727987
Xylella fastidiosa, the causal agent of several diseases in crops of economic interest,
could be rapidly transmitted and spread throughout the agroecosystem landscape by
xylem sap-feeding
insects. Chemical signals in the environment drive the behaviour
of insects. Attractive or repulsive responses to signals may affect insects’ fitness, survival
and reproduction, and elicit different movement patterns. Specific movement
patterns derived from olfactory cues towards the selection of plants for feeding may
trigger the transmission of the pathogen by the insect. Thus, understanding vectors’
olfactory response and movement parameters are of utmost importance. This work
aimed to assess the olfactory response of Philaenus spumarius and Cicadella viridis
adults to two Volatile Organic Compounds (VOCs) (cis-3-
hexenyl
acetate and cis-3-
hexen-
1-
ol)
present in almond, olive and vine leaves. Insects’ behavioural responses
were conducted in a four-arm
olfactometer, and the two aforementioned VOCs were
tested at different concentrations (5, 10, 20 and 30 μg/μl). At the lowest concentration,
females of P. spumarius were significantly attracted by the two VOCs. At the
highest concentrations, no significant differences were detected among treatments.
Cicadella viridis individuals showed no significant differences in their choice at any
concentration. Additionally, the walking movement of these insects was also studied
in the absence of food. Females of P. spumarius and C. viridis can walk significantly
more at a significantly higher velocity than males. Knowledge of the olfactory response
of X. fastidiosa vectors and their movement parameters can be essential to
develop new tools to limit the spread of this phytopathogen.
