Confirmation of coffee related Xylella fastidiosa vectors (Cicadellidae) in Costa Rica

Xylella fastidiosa is a vector-transmitted plant pathogen of economic importance. In Costa Rica, X. fastidiosa is widespread in coffee plantations, positive coffee plants are mostly asymptomatic, or present mild symptoms related to “crespera” disease, as reported previously. Despite this, there is scarce information regarding vector biology in this pathosystem. Past studies have shown that there is great diversity of Hemiptera (Cicadellidae and Clastopteridae) in coffee production zones affected by X. fastidiosa in Costa Rica; these insects represent potential X. fastidiosa vectors. However, to our knowledge, confirmation of vector status remains unsettled. In this work, we identified within the population of Cicadellidae from a coffee plantation in Carrizal de Alajuela (coffee producing zone in the northern part of Costa Rican central valley), a series of specific species of leafhoppers as true vectors of X. fastidiosa related to coffee in Costa Rica. To achieve these results, insects were collected in field conditions, and Cicadellidae were identified, classified, and grouped for further analysis. All assays were set up in greenhouse conditions. The ability of these vectors to feed and survive on coffee plants was assessed. Artificial transmission assays, revealed the presence of the bacteria, using qPCR after feeding in at least 6 species of leafhoppers. MLST typing was done to confirm circulating ST. Transmission assays were done on X. fastidiosa free coffee plants, detection of the bacteria was achieved in plants as soon as six months, positive plants did not shown symptoms up to 2 years. These findings contribute to the integral understanding of the pathosystem and for the development of mitigation strategies.