Penicillium polonicum causing a postharvest soft rot of cactus pear fruits.

Since 2007, a soft rot associated with a blue mold was observed on fruits of cactus pear (Opuntia ficus-indica) in packinghouses and storage facilities in two major producing areas of the Catania province (eastern Sicily). Isolations from symptomatic fruits yielded consistently a fungal species identified as Penicillium polonicum on the basis of both morphological characteristics and sequencing of part of the β-tubulin gene. Symptoms were reproduced by artificially inoculating mature cactus pear fruits with a conidial suspension of a P. polonicum isolate obtained from fruits with natural infections. This is the first report of P. polonicum as both a resident and a pathogen on cactus pear worldwide.