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Xylem-feeding is apparently the only requirement making an insect a competent vector of the bacterium Xylella fastidiosa, an organism responsible for the devastation of the Southern Italian olive forest and nowadays considered one of the most feared threats to agriculture and landscape in Europe, including vineyards. Here, we used the direct current-electrical penetration graph (DC-EPG) technique to compare and describe the feeding behaviour on grapevine of four xylem-feeding species considered candidate vectors of X. fastidiosa widespread in Europe, namely two spittlebugs (the meadow spittlebug Philaenus spumarius and the spittlebug Neophilaenus campestris) and two sharpshooter leafhoppers (the rhododendron leafhopper Graphocephala fennahi and the green leafhopper Cicadella viridis). We created a standard for the analysis of EPG waveforms recorded with a DC-EPG device, describing feeding activities performed by these insects from stylet insertion into the plant to withdrawal. This standard, along with freely available software, has been developed to harmonize the calculation of feeding behavioural parameters in xylem-feeders. The most relevant differences between the two vector taxa were the probing frequency and the dynamics of xylem ingestion. Sharpshooters tended to perform significantly more probes than spittlebugs. In contrast, the latter spent longer times in low-frequency xylem ingestion, characterized by scattered contractions of the cibarial dilator muscle interspersed with periods of pump inactivity. Cicadella viridis was the species displaying the highest frequency of the electrical pattern found to be associated with X. fastidiosa inoculation in spittlebugs (Xe). Feeding behavioural data presented here represent an important step forward for deepening our knowledge of xylem-sap feeding insects' interaction with both the host plants and the bacterium they transmit.

The Direct Current-Electrical Penetration Graph (DC-EPG) technique was used to compare and describe the feeding behaviour on grapevine of four xylem sap-feeding species considered candidate vectors of X. fastidiosa and widespread in Europe: the meadow spittlebug Philaenus spumarius, the spittlebug Neophilaenus campestris, the rhododendron leafhopper Graphocephala fennahi and the green leafhopper Cicadella viridis. The four species were settled on potted grapevine plants for a period of 6 hours and the feeding activities performed by these insects, from stylet insertion into the plant to withdrawal were recorded by DC-EPG coupled with Stylet+d software. Characteristic waveforms were marked with Stylet+a software and analysed by the macro XylFeed. The raw data of the sequential and non-sequential EPG parameters generated by the XylFeed are reported in this database as part of the connected publication.

The software “XylFeed” is designed as MS Excel macro, developed to analyse essential DC-EPG (Direct Current-Electrical Penetration Graph) waveform variables for European xylem sap-feeding insects (spittlebugs and sharpshooters). DC-EPG waveforms must be manually marked in ‘Stylet+a’ (EPG Systems, Wageningen, Netherlands) or comparable software previously to allow a calculation in “XylFeed”. The software enables the analysis of the probing and feeding activities of European xylem sap-feeding insects through a calculation of sequential and non-sequential EPG variables. A detailed description of the software usage is provided in the Supplementary Material of the connected publication, while software output variables are listed and defined within the software.

The spread of pests and pathogens is increasingly intensified by climate change and globalization. Two of the most serious insect pests threating European viticulture are the European grape berry moth, Eupoecilia ambiguella (Hübner) and the European grapevine moth Lobesia botrana (Denis & Schiffermüller). Larvae feed on fructiferous organs of grapevine Vitis vinifera, resulting in high yield and quality losses. Under the aspects of integrated pest management, insecticide measures are only reasonable when other control strategies become ineffective. In order to support the development of novel decision support system for the application of insecticides, the aim of this thesis was to decipher plant-specific factors, which affect the short-range attraction and oviposition of L. botrana and E. ambiguella. The focus was set on the visual, volatile, tactile and gustatory stimuli provided by their host plant after settlement. The use of artificial surfaces as model plant showed that oviposition of both species is affected by the color, the shape and the texture of the oviposition site. To explain a susceptibility of certain grapevine cultivars and phenological stages of the berries to egg infestations, we analysed and compared the chemical composition of the epicuticular waxes of the berry surface as well as the volatile organic compounds emitted by the berries. Thereby it turned out that the attractiveness to wax extracts decreased during ripening of the berries, highlighting a preference of earlier phenological stages of the berries for oviposition. In addition, grapevine cultivars exhibited variations in their volatile composition. The principle components perceived by female’s antennae could not explain the differentiation between cultivars, suggesting volatiles do not trigger orientation to certain cultivars. Furthermore, a method was developed to measure real-time behavioural response of female moths to volatiles. The setup allowed to quantify the orientation to a vo