Collection of data and information in Balearic Islands on biology of vectors and potential vectors of Xylella fastidiosa (GP/EFSA/ALPHA/017/01)

Abstract

The pathogenic bacteria Xylella fastidiosa (Proteobacteria: Xanthomonadaceae) was detected in the Balearic Islands in October 2016. In November 2017 EFSA granted the data collection on the biology of vectors in the Balearic Islands. The grant included the following objectives: i) Data collection in the Balearic Islands by macrocosm and microcosm observations of the vectors in the major agroecosystems; ii) Proposal on field sampling protocols of vectors; iii) Identification of the major vectors of X. fastidiosa in the Balearic Islands. For the study of macrocosm, samplings were conducted in Majorca, Ibiza, Formentera and Minorca. For the microcosm study, cages containing one male and one female of P. spumarius and one plant per cage were placed at semi-field conditions. For the development of the guidelines, literature research was conducted. For the vector competence experiments, field collected insects were caged with X. fastidiosa free plants of Medicago sativa. From the macrocosm results, two Aphrophoridae (Hemiptera; Cicadomorpha) species of vectors have been detected in the Balearic Islands, Philaenus spumarius and Neophilaenus campestris. Nymphs of Aphrophoridae were more abundant from early March to the end of May in the cover vegetation of olive crops, followed by vineyard and almond ones. Adults of Aphrophoridae were more abundant in the cover vegetation from May to June and from October to November, in the tree canopy from June to August and in the border vegetation from August to October. The microcosm trials showed that P. spumarius and N. campestris were able to develop in Lavandula dentata, Rosmarinus officinalis, Menta x piperita, Pistacia lentiscus and Ocinum basilicum. The average prevalence of X. fastidiosa from vectors collected from 2017 to 2020 was 23 %. Adults of P. spumarius and N. campestris collected from infected areas of Majorca successfully transmitted X. fastidiosa to uninfected plants of M. sativa.