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Alternative inoculum sources for fire blight: the potential role of fruit mummies and non‐host plants
Author(s) -
Weißhaupt S.,
Köhl L.,
Kunz S.,
Hinze M.,
Ernst M.,
Schmid A.,
Voegele R. T.
Publication year - 2016
Publication title -
plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.928
H-Index - 85
eISSN - 1365-3059
pISSN - 0032-0862
DOI - 10.1111/ppa.12431
Subject(s) - biology , erwinia , overwintering , fire blight , orchard , rootstock , host (biology) , population , malus , pathogen , shoot , horticulture , botany , bacteria , ecology , microbiology and biotechnology , genetics , demography , sociology
Fire blight is the most damaging bacterial disease in apple production worldwide. Cankers and symptomless infected shoots are known as sites for the overwintering of Erwinia amylovora , subsequently providing primary inoculum for infection in the spring. In the present work, further potential sources of inoculum were investigated. Real‐time PCR assays covering a 3‐year‐period classified 19·9% of samples taken from fruit mummies as positive. Bacterial abundance in fruit mummies during autumn, winter and spring was up to 10 9 cells per gram of tissue and correlated well with later infection rates of blossoms. Blossoms of non‐host plants growing close to infected trees were also shown to be colonized by E. amylovora and to enable epiphytic survival and propagation of bacteria. The results indicate a potential role of fruit mummies and buds in overwintering and as a source of primary inoculum for dissemination of the pathogen early in the growing season. Non‐host blossoms may also serve as an inoculum source in the build‐up of the pathogen population. Both aspects may contribute significantly to the epidemiology of E. amylovora . The significance of infected rootstocks as an inoculum source is also discussed. Fruit mummies might be used to determine pathogen pressure in an orchard before the beginning of the blooming period.