BACKGROUND
Olive quick decline syndrome (OQDS), caused by Xylella fastidiosa subsp. pauca ST53, has devastated olive groves in Apulia (southern Italy), severely impacting olive production and rural agroecosystems. High populations of the key insect vector Philaenus spumarius (Hemiptera: Aphrophoridae) and agricultural landscapes dominated by susceptible olive cultivars have driven epidemic spread. Replanting with resistant olive cultivars is currently supported as a key restoration strategy for olive growers and olive oil industry. This study evaluated the transmission efficiency of X. fastidiosa ST53 by P. spumarius from and to resistant olive cultivars Leccino and FS17 compared with susceptible ones, using field and controlled experiments conducted over 3 years.
RESULTS
Resistant olive cultivars acted as poor bacterial sources for vector acquisition, resulting in very low subsequent inoculation rates of the bacterium. In contrast, as recipient plants, resistant and susceptible cultivars were infected at similar rates, indicating that inoculation efficiency of infectious vectors did not differ among olive genotypes. Inoculation success was primarily influenced by the number of infectious insects feeding on recipient plants, whereas acquisition depended mainly on bacterial load in source plants, which was consistently lower in resistant cultivars.
CONCLUSIONS
The presence of resistant olive varieties into agricultural landscapes could notably reduce epidemic spread by limiting vector infectivity and pathogen availability for transmission. However, vector population control and inoculum reduction remain essential components of effective OQDS management. These findings support integrated management strategies combining host resistance and vector management and provide valuable parameters for epidemic modelling and disease control planning. © 2026 Society of Chemical Industry.