Archivio Journal of Plant Pathology

Abstract:

In autumn 2011, a severe rot of fruits was observed in some quince (Cydonia oblonga Mill.) plants located in San Lorenzo Nuovo (province of Viterbo) and Frascati (province of Rome). Affected fruits showed rotting that evolved rapidly, covering their entire surface and causing mummification. Some mummified fruits dropped prematurely, although most of them persisted on the trees. No symptoms were observed on leaves or branches of the affected plants. A fungus consistently isolated from rotting fruits was identified as Fusicoccum aesculi Corda, the anamorph of Botryosphaeria dothidea Ces. et de Not., based on morphologi- cal characters (Sutton, 1980). The rDNA ITS regions of two fun- gal isolates, (ER1739, ER1757) one from each location, were am- plified by PCR using the universal primers ITS1 and ITS4. The sequences (GenBank accession No. JQ686227 and JQ686228) re- vealed 100% homology with those of 21 isolates of B. dothidea retrieved from GenBank, confirming the morphological identifi- cation. Koch’s postulates were verified on eight detached fruits from healthy C. oblonga trees. Seven days post inoculation with both fungal isolates, rotting initiated at the site of infection and expanded rapidly to the rest of the fruit. Non-inoculated controls remained healthy. Fruits rots and mummifications were similar to those observed in naturally infected trees in the field. The anamorph of B. dothidea was reisolated from all the inoculated fruits but not from the controls. B. dothidea is known to infect the fruits of several hosts, among which olive drupes (Lazzizzera et al., 2008), but this is the first time that it is identified as the ca- sual agent of fruit rot of quince in Italy.