Fruit Rot Caused by Penicillium italicum on Lemon (Citrus aurantifolia) in Colima, Mexico

Postharvest rotting caused by Penicillium italicum Wermer is responsible for significant economic losses of orange (Citrus sinensis (L.) Osbeck) and lemon (C. limon Burm. f.) worldwide, but until now was not described on lemons (C. aurantifolia (Chistm.) Swingle) in Mexico. During May 2002, we analyzed 400 fruits of lemon collected in the state of Colima, which is the most important lemon producer in Mexico. Rotting and softened areas covered with a white mycelium and blue conidia were observed on approximately 30% of the fruits. Affected tissue was plated onto potato dextrose agar (PDA) for fungal isolation and identification. Following the morphological criteria (1) and the internal transcribed spacer 1 (ITS1), 5.8S, and ITS2 region of the ribosomal DNA (2) (GenBank Accession No. DQ991463), the fungus was identified as P. italicum and deposited in the Coleccion Microbiana y de Cultivos Celulares CINVESTAV-IPN, Mexico. For the pathogenicity test, the fungus was grown on PDA for 1 week. Four drops (15 μl ...