FIRST REPORT OF PESTALOTIOPSIS CLAVISPORA CAUSING POSTHARVEST FRUIT ROT OF LOQUAT IN SPAIN
L. Palou, C. Montesinos-Herrero, A. Guardado, V. Taberner
pain is the second loquat (Eriobotrya japonica Lindl.) producer in the world. In a survey for postharvest fruit losses, brownish spots located mainly at the stilar end were observed which, at 20oC, expanded rapidly, turning dark brown to black, and developed a compact white mycelium. The potential causal agent (isolate IVIA NiAA-33) was re- covered and identified at the Spanish Type Culture Collec- tion (CECT, UV, Valencia, Spain). The fungus grew fast on potato dextrose and malt extract agar at 26oC covering the entire plate with a velvety white mycelium with numerous black globose acervuli. The plate reverse showed orangish tonalities. Conidia were fusiform (26×8 μm), five-celled, with hyaline apical and basal cells and dark brown median cells, and showed one short basal and 2 to 4 long apical ap- pendages. The identification as Pestalotiposis clavispora (G.F. Atk.) Steyaert was molecularly determined by sequencing the rDNA ITS1-5.8S-ITS2 region (GenBank accession No. KC153999) and the D1/D2 region in the 5’ end of the 28S rDNA gene (KC154000). BLAST analysis showed in both cases 100% identity with P. clavispora (EU342214 and JN940831). To fulfill Koch’s postulates, 5-mm diameter mycelial plugs from 7-day-old colonies were transferred to skin wounds on superficially disinfected loquats cv. Algerie. While all inoculated fruits developed lesions after 14 days at 20oC and P. clavispora was consistently reisolated from these lesions, no infection was observed on wounded but non inoculated control fruits. To our knowledge, this is the first report of P. clavispora causing postharvest fruit rot of loquat in Spain. This fungus was reported as the cause of stem-end rot of avocado (Valencia et al., 2011) and P. guepini as the agent of a loquat disease (Perelló and Larran, 1999).