Articles
Investigation on the involvement of Botryosphaeriaceae in recent walnut dieback in French orchards
Article number
1420_35
Pages
259 – 266
Language
English
Abstract
A recent national survey revealed a recrudescence of wood dieback associated with blight, cankers and fruit necrosis in French walnut orchards.
A preliminary study reported that these symptoms were associated with the presence of Phomopsis, Colletotrichum, Botryosphaeria, Neofusicoccum and Fusarium. Between 2020 and 2021, 641 symptomatic and asymptomatic samples (twigs and fruits) were collected in 12 walnut orchards from the two main French production areas to focus on the nature and distribution of Botryosphaeriaceae species.
Culturing fragments of wood canker and fruit necrosis revealed that, among the cultivated diversity, two Botryosphaeriaceae species were mainly associated with these symptoms: Botryosphaeria dothidea and Neofusicoccum parvum, whatever the production area.
Pathogenicity tests were performed in both greenhouse and experimental orchards on attached shoots.
Results confirmed that B. dothidea and N. parvum induced necrosis on shoots. N. parvum isolates were more aggressive in both experiments, than B. dothidea. This work is the first report to identify the Botryosphaeriaceae fungal species causing this complex disease in French walnut orchards.
It would be helpful to better understand the influence of environmental conditions on disease development for a better management control.
A preliminary study reported that these symptoms were associated with the presence of Phomopsis, Colletotrichum, Botryosphaeria, Neofusicoccum and Fusarium. Between 2020 and 2021, 641 symptomatic and asymptomatic samples (twigs and fruits) were collected in 12 walnut orchards from the two main French production areas to focus on the nature and distribution of Botryosphaeriaceae species.
Culturing fragments of wood canker and fruit necrosis revealed that, among the cultivated diversity, two Botryosphaeriaceae species were mainly associated with these symptoms: Botryosphaeria dothidea and Neofusicoccum parvum, whatever the production area.
Pathogenicity tests were performed in both greenhouse and experimental orchards on attached shoots.
Results confirmed that B. dothidea and N. parvum induced necrosis on shoots. N. parvum isolates were more aggressive in both experiments, than B. dothidea. This work is the first report to identify the Botryosphaeriaceae fungal species causing this complex disease in French walnut orchards.
It would be helpful to better understand the influence of environmental conditions on disease development for a better management control.
Publication
Authors
C. Masson, A. Moronvalle, A. Verhaeghe, M. Belair, G. LeFloch, F. Pensec, A. Picot, M.-N. Hébrard, Y. Laloum
Keywords
Botryosphaeriaceae, walnut dieback, diagnosis, French walnut orchards
Groups involved
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