Pathogenicity of Phoma betae isolates from red beet (Beta vulgaris) at seed farms in Canterbury, New Zealand
Phoma betae is an economically important pathogen of red beet causing pre-emergence seedling damping, leaf spot and root rot. However, the pathogenicity of P. betae is unknown in New Zealand despite the economic importance of this pathogen. Twenty-five isolates were collected from a survey of red beet seed farms in Canterbury, New Zealand during 2016/2017 and three of these PB101 (from seeds), PB103 (from roots) and PB106 (from leaves) were used for pathogenicity testing of two red-beet cultivars. Isolate PB106 was further used to investigate its effects on spinach and fodder beet as well as red beet under greenhouse conditions. All three P. betae isolates were pathogenic on both red-beet cultivars tested, causing leaf-spot symptoms. Isolates PB101 and PB106 produced significantly larger leaf-spot lesions (P<0.001) compared with PB103. Phoma betae isolate PB106 was pathogenic to both red-beet cultivars, spinach and fodder beet but fodder beet was less susceptible than the other species tested. Regardless of cultivar, P. betae is an important pathogen of beets and is capable of causing leaf spots.... [Show full abstract]
KeywordsPhoma betae; pathogenicity; Beta vulgaris; seed farms; red beet; spinach; fodder beet; New Zealand
Fields of Research0703 Crop and Pasture Production; 0706 Horticultural Production; 070603 Horticultural Crop Protection (Pests, Diseases and Weeds); 07 Agricultural and Veterinary Sciences
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