Pest Management Science (2020) 76, 1333-1343

Pedro Romon-Ochoa, Caroline Gorton, Alex Lewis, Sietse van der Linde, Joan Webber and Ana Pérez-Sierra (2020)
Hypovirulent effect of the Cryphonectria hypovirus 1 in British isolates of Cryphonectria parasitica
Pest Management Science 76 (4), 1333-1343
Abstract:
Background
Chestnut blight, caused by Cryphonectria parasitica, is controlled in many European countries by the naturally occurring mycovirus Cryphonectria hypovirus 1 (CHV-1). During surveys of recently identified chestnut blight outbreak in England, CHV-1 was detected in several individuals of the pathogen isolated from affected trees. We investigated two of these CHV-1-infected isolates (L-6 and Db-1) as potential biocontrol agents for deployment in the UK comparing their virulence against virus-free (M1275) and hypovirulent (M784) European isolates by inoculating sweet chestnut seedlings.
Results
Both the European CHV-1 M784 hypovirulent isolate and UK L-6 isolate formed significantly smaller lesions in sweet chestnut seedling bark than the other three isolates (Db-1, and virulent isolates FTC121 and M1275). The highest virus concentration was detected in isolate M784, followed by L-6, with the lowest concentration in isolate Db-1. White colony colouration indicative of hypovirulence was common in colonies re-isolated from smaller lesions, and the same isolates also tended to be slower growing in culture, have a higher virus concentration, and caused less epicormic growth and fewer stromata to be present in plants. L-6 and Db-1 virus sequences, respectively, matched the virus haplotype E-5 detected previously in Switzerland and a mutation of the same subtype I haplotype.
Conclusion
Isolate L-6 could potentially act as biocontrol for chestnut blight outbreaks in the UK but further laboratory and field experiments are needed.
(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): Joan F. Webber

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
evaluation - screening - selection

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Cryphonectria parasitica	Chestnut (Castanea)	United Kingdom
Cryphonectria parasitica hypoviruses (antagonist)	Cryphonectria parasitica	Chestnut (Castanea)	United Kingdom