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Characterization of Neofabraea actinidiae and N. brasiliensis as causal agents of apple bull’s-eye rot in southern Brazil

Bogo, Amauri, Comparin, Carla C., Valdebenito Sanhueza, Rosa M., Ritschel, Patricia, Casa, Ricardo T., Silva, Fábio N., Everhart, Sydney E.
Canadian journal of plant pathology 2018 v.40 no.2 pp. 229-237
Neofabraea, apples, bull's eye rot, fruits, growth retardation, hybrids, lesions (plant), median effective concentration, mycelium, pH, pectin lyase, pyrimethanil, temperature, thiophanate-methyl, triflumizole, Brazil
The causal agents of apple bull’s-eye rot in southern Brazil have recently been described as Neofabraea actinidiae and N. brasiliensis. Isolates of both species were evaluated for response of mycelial growth index (MGI) to different temperatures, enzyme production, mycelial growth inhibition and effective concentrations (EC₅₀ and EC₁₀₀) of the fungicides triflumizole, pyrimethanil and thiophanate methyl, as well as aggressiveness on fruits of ‘Fuji’ hybrid and ‘Pink Lady’. There was significantly lower mycelium growth in N. brasiliensis compared with N. actinidiae at all temperatures tested. Neither species grew at 3 and 32°C. There were minor differences in production of enzymes in the two species, with all N. brasiliensis isolates showing no production of pectolyase at pH 7. The lowest EC₅₀ and EC₁₀₀ values were observed with thiophanate methyl. In general, ‘Fuji’ fruits were more susceptible to Neofabraea infection and had larger lesions, while N. brasiliensis isolates showed greater aggressiveness on ‘Fuji’ hybrid and ‘Pink lady’ fruits compared with N. actinidiae.