ISHS Acta Horticulturae 587: International Symposium on Asian Pears, Commemorating the 100th Anniversary of Nijisseiki Pear
VENTURIA NASHICOLA: PATHOLOGICAL SPECIALIZATION ON PEARS AND CONTROL TRIAL WITH RESISTANCE INDUCERS |
| Authors: | H. Ishii, H. Watanabe, K. Tanabe |
| Keywords: | Japanese pear, Pyrus pyrifolia, pear scab, race, disease resistance, acibenzolar-S-methyl |
| Abstract:
Venturia nashicola, the scab fungus of Japanese (Pyrus pyrifolia var. culta) and Chinese (P. ussuriensis) pears, is distinct from the European pear scab fungus V. pirina. Pathological specialization was found in V. nashicola using inoculation tests on young potted pear trees. Two strains of this fungus (race 1), isolated from the commercial Japanese pear cultivar (cv.) ‘Kousui’, were pathogenic on ‘Kousui’, but not on the wild pear strain ‘Mamenashi 12’ (species unknown). Out of the four strains of V. nashicola isolated from ‘Mamenashi 12’, two strains (race 2) showed pathogenicity specific to ‘Mamenashi 12’. However, other strains (race 3) showed pathogenicity both to ‘Mamenashi 12’ and to ‘Kousui’. The non-commercial Japanese pear cv. ‘Kinchaku’ was resistant to all the three races of V. nashicola, strengthening the suggestion that this cultivar could be used as a source of resistance in breeding programs. The non-fungitoxic benzothiadiazole compound acibenzolar-S-methyl, known as a systemic resistance inducer, has shown high control efficacy against Japanese pear scab in field trials. | |
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