Postharvest fungal diseases of loquat cv. ‘Algerie’ in Spain

Abstract

Spain is the second world largest producer and the first exporter of Japanese loquat (Eriobotrya japonica (Thunb.) Lindl.) for fresh consumption. More than 50% of the cultivated area is located in Alacant province (SE of Spain), where about 98% of total production belongs to loquat cv. ‘Algerie’, which is mainly exported to European Union (EU) markets. For two consecutive seasons, commercially grown ‘Algerie’ loquats from two orchards were used to assess disease caused by both latent and wound pathogens. Selected healthy fruit were either surface-disinfected or artificially wounded in the rind and incubated in humid chambers at 20°C for up to 5 weeks. Additionally, disease was also assessed on commercially handled fruit (manually selected and packaged) stored at 5°C for up to 12 weeks; no loquat postharvest treatments are currently authorized in the EU. Isolated fungi were incubated on potato dextrose agar (PDA) plates at 25°C for purification and subsequent morphological and molecular identification. Pathogenicity of common isolates was demonstrated by fulfilling Koch’s postulates. Disease development was assessed on artificially inoculated loquats stored at either 20 or 5°C. Regardless of type of infection and postharvest fruit management, the most frequent postharvest diseases were black spot caused by Alternaria alternata and blue mold caused by Penicillium expansum. In addition, gray mold caused by Botrytis cinerea was frequently observed on both artificially wounded and commercially handled fruit, whereas anthracnose caused by Colletotrichum gloeosporioides was frequently observed on surface-disinfected loquats. Other minor pathogens that were found causing latent infections, especially in the fruit stem-end, were Pestalotiopsis clavispora and Diplodia seriata.