Seasonal olfactory response of Philaenus spumarius (Hemiptera: Aphrophoridae) towards traditional Portuguese olive cultivars

Abstract In Portugal, the strength of the olive sector relies on the great genetic heritage of traditional olive cultivars. However, this genetic heritage is threatened by the causal agent of olive quick decline syndrome (OQDS), the phytopathogenic bacteria Xylella fastidiosa, reported for the first time in 2019 in the country. This vector-borne pathogen is transmitted by xylem-feeding insects such as Philaenus spumarius which is considered the main European vector. Since there is no cure for this pathogen, the implementation of an integrated approach against the vectors should be considered to prevent and limit the spread of X. fastidiosa. In this sense, an in-depth assessment of the host plant preferences of the main European vector of X. fastidiosa is crucial to understand their seasonal dynamics towards olive cultivars to determine the most susceptible to vector attack. This work aimed to assess the olfactory response of P. spumarius, to five traditional Portuguese olive cultivars: "Cobrançosa," "Negrinha de Freixo," "Santulhana," "Madural," and "Verdeal Transmontana" in two separate seasons (Spring and Autumn). Our results showed that P. spumarius presented significantly different olfactory responses toward the different cultivars under study. In Spring, females and males were significantly attracted to "Negrinha de Feixo"; in Autumn, females were significantly attracted to "Cobrançosa". Also, in general, the olfactory response toward the five cultivars was sex-dependent. Our results suggest that in Spring, the cultivar "Negrinha de Freixo" can be more susceptible to P. spumarius and that the olfactory response towards the olive cultivars can vary throughout the life cycle of the vector. Our results can help future implementation of approaches to manage the vector and the spread of X. fastidiosa.