Secondary spread of Clavibacter michiganensis subsp. michiganensis in nurseries and the conditions leading to infection of tomato seedlings

摘要

Frenkel, O., Borenstein, M., Shulhani, R., Sharabani, G., Sofer, M., Abu-Moch, F., Lofthouse, M., Manulis-Sasson, S., and Shtienberg, D. 2015 Secondary spread of Clavibacter michiganensis subsp. michiganensis in nurseries and the conditions leading to infection of tomato seedlings. European Journal of Plant Pathology XX:XXX-XXX. Infected seedlings are one of the most important primary sources of inoculum of Clavibacter michiganensis subsp. michiganensis (Cmm), the causal agent of bacterial canker and wilt of tomatoes, in commercial production plots. In this study we tested the hypothesis that a low number of infected source seedlings may give rise to a large number of infected seedlings in the nursery even when careful measures are taken. It was found that the pathogen dispersed spatially from root-inoculated source seedlings and colonized the leaf surfaces of surrounding seedlings to distances of 65-75 cm. A sub-irrigation system reduced, but did not prevent, Cmm dispersal. Infections by epiphytic Cmm populations can occurred under a wide range of temperature conditions, seedling ages and foliar wetness periods. The results emphasize the need to minimize the primary infectious sources as well as developing new strategies to reduce the dispersal during the nursery stage.