A new rot of stored apples was observed in local and export markets on apples that were grown in the south-central region of Chile during 2004. Circular, pale brown spots with a darker outer ring were observed at least 3 months after harvest in cvs. Braeburn, Fuji, Granny Smith, Pink Lady, and Royal Gala. Lesions developed from lenticel cavities or wounds and reached 2 to 3 cm in diameter after 1 week at room temperature. Symptoms resembled those produced by the bull's eye rot pathogens on apple that occur in other parts of the world. Acervuli developed in the rotted areas, and microscopic examination revealed the presence of the fungus Neofabraea alba (Guthrie) (anamorph Phlyctema vagabunda Desm.) characterized by production of curved macroconidia and absence of microconidia (1). Pure culture on potato dextrose agar (PDA) yielded a characteristic white sterile mycelium. Four cv. Pink Lady apples were wound inoculated with mycelium of the pathogen and four apples were wound inoculated with a 5 × 104 CFU/ml conidial suspension. Four apples were wounded and inoculated with sterile water as a negative control. The fruit was held at 20°C. Symptoms appeared after 4 and 5 days in the mycelium and conidial inoculated apples, respectively. Resulting symptoms were similar to those originally observed. Abundant macroconidia were produced at the inoculation sites, and a sterile, white mycelium was recovered after isolation on PDA. To our knowledge, this is the first report of apple fruit rot caused by N. alba in Chile.
Reference: (1) J. L. Henriquez et al. Plant Dis. 88:1134, 2004.
