Phytopathology (2019) 109, 2055-2063

Francesca Dennert, Joana Beatrice Meyer, Daniel Rigling and Simone Prospero (2019)
Assessing the phytosanitary risk posed by an intraspecific invasion of Cryphonectria parasitica in Europe
Phytopathology 109 (12), 2055-2063
Abstract: Intraspecific cryptic invasions may occur when new strains of an invasive species are introduced into an area where this species had already been introduced previously. In plant pathogens, such invasions are not well studied, even if, potentially, they can have severe consequences. Here, we investigated the effects of a potential intraspecific invasion in Europe of Cryphonectria parasitica, the causal agent of chestnut blight. Specifically, we tested the hypotheses that (i) non-European strains are more virulent on Castanea sativa than those already present in Europe because they have never encountered this new host, and (ii) the variation in virulence among strains is higher within native than within introduced populations. In a greenhouse, 2-year-old C. sativa seedlings were inoculated with Cryphonectria parasitica strains from South Korea, the United States, and Switzerland, and lesion development and seedling mortality were recorded weekly. Additionally, growth and sporulation of the strains were measured in vitro on agar medium at 15 and 24°C. Although lesion growth was similar for all strains, seedlings inoculated with strains from South Korea and Switzerland died faster than seedlings inoculated with strains from the United States. Moreover, in vitro strains from South Korea grew faster and produced more spores at both temperatures than the strains from the other two countries. In conclusion, our results did not support the two hypotheses. All strains, regardless of their origin, were found to be highly virulent on the inoculated chestnut seedlings. Nevertheless, current phytosanitary measures to avoid the introduction of new genotypes of C. parasitica into Europe should be further implemented.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Francesca G. Dennert, Daniel Rigling

Research topic(s) for pests/diseases/weeds:
quarantine treatments/regulations/aspects

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Cryphonectria parasitica	Chestnut (Castanea)	Switzerland
	Cryphonectria parasitica	Chestnut (Castanea)	United Kingdom
	Cryphonectria parasitica	Chestnut (Castanea)	Korea-South