Susceptibility of apple fruits from selected cultivars to the Colletotrichum acutatum species complex

Abstract

The pathogenicity of five isolates of Colletotrichum acutatum species complex (CASC) was tested on artificially injured apple fruits of the cultivar 'Golden Delicious' under laboratory conditions. Then, ten apple cultivars were tested for their relative susceptibility to CASC. Differences in the pathogenicity of the CASC isolates were confirmed in the test. The highest degree of pathogenicity was showed by the isolates from the strawberry and DCSBPM J1 from the apple. No cultivars were resistant to the pathogen. The disease incidence ranged from 57.5% to 100%. The individual cultivars showed different susceptibility to the tested isolates. The cultivars 'Braeburn', 'Jonagold' and 'Rubinola' showed the least susceptibility to the pathogen, while the cultivars 'Jonagored' and 'Otava' were recorded as the most susceptible to CASC. All the tested isolates were confirmed, by the conventional PCR method, to belong to CASC. The sequences of isolates DCSBPM J1 and DCSBPM 1209 were deposited in the GenBank.

Keywords

• bitter rot
• malus domestica
• cross-infection
• resistance test
• virulence test