This project will be conducted within the Swiss National Competence Center for Fire Blight at Agroscope Changins-Wädenswil. Our base-funded activities take a comprehensive approach to combating fire blight and integrate extension duties (advisory, monitoring, diagnostic, forecasting) with the research activities of a bacteriologist. Research is primarily dependent on external projects. The objectives of this project can only be achieved with additional funding provided.
This project will study currently pressing issues related to pathogen inoculum sources and latent infections in trees and nursery material. The tasks set-forth will build upon our research experience with pathogen detection, pathogen genetics/genomics, and pathogen-host interactions. The strong extension and plant inspection experience of the applicants provides a unique platform for integrating project results into the development of practical guidelines for sustainable management of fire blight in Switzerland. The results of this project are equally relevant to organic, conventional and low input apple/pear production systems.
Module 1 will apply genomics to develop methods for distinguishing pathogen strains at the local level. Specifically determining the inoculum source for infections in orchards and nurseries (are the strains infecting an orchard truly originated from nearby, old growth trees or wild species?). Currently this is not possible and control strategies rely on the assumption that infected trees are the inoculum source for fire blight outbreaks in high-value objects such as orchards and nurseries. The techniques developed in this project will enable such strain detection and improve our ability to detect inoculum sources in the environment. This will have fundamental importance in optimizing control guidelines.
Module 2 Latent fire blight infection (asymptomatic infections) presents a major problem for preventing spread of fire blight within a region and from import of infectious trees. This project will develop methods for pathogen detection in asymptomatic tissues and examine environmental factors that lead to such infections. This is particular important in rootstock infections since, outside direct infections via wounds or sucker shoots, these develop via movement of the pathogen through asymptomatic plant tissues. Our project will survey the severity of this emerging threat in Switzerland and examine factors that lead to susceptibility to rootstock blight (climate, pruning, scion variety).
