First report of Aspergillus flavus causing fruit rots of peaches in Greece

In July 2005, rotted peaches (about 1% of the total) of the cultivars ‘Sun Crest’, ‘Andross’ and ‘Sun Cloud’ were observed in commercial orchards in Imathia County (northern Greece). Infected tissues were pale and water soaked, and the spores were green and powdery, easily liberated when matured (Fig. 1). Aspergillus flavus was isolated and identified based on morphological characteristics. Isolation of the pathogen was made on acidified-PDA (2.5 ml 85% lactic acid per L nutrient medium). The plates were incubated at 23ºC for 5 to 7 days. Koch’s postulates were completed in the laboratory by inoculating mature peach fruits (cv Andross). Peach fruit were surface sterilized by dipping in a 0.1% chlorine solution, allowed to dry in a laminar flow hood, wounded with a sharp glass rod of 2 mm in diameter, and a 40 µl drop of a 5 x 10⁵ conidia per ml suspension of fungus was placed over each wound. There were 30 inoculated and 30 control fruits (similarly wounded and inoculated with a 40 µl drop of sterile-distilled water) in a randomized design and incubated at 24-26°C for 7 days. Koch’s postulates were satisfied after re-isolating the fungus from inoculated fruit that developed symptoms similar to those observed on fruit collected from orchards.

This is the first report of Aspergillus flavus causing a rot of peaches in Greece. Fruit rots caused by A. flavus have been reported in peach orchards in other countries around the world (Jamaluddin, 1980; Singh & Prashar, 1989). Measures should be taken to limit any possible spread of this pathogen in future, since toxigenic strains of Aspergillus produce aflatoxins that are known carcinogens and toxic to the liver (Marasas & Nelson, 1985; Molina & Giannuzzi, 2002).