Clarification of the agents causing blue mold storage rot upon various flower and vegetable bulbs: implications for mycotoxin contamination

A considerable number of blue mold rot reports of various commercially grown bulbs and vegetables in the literature have been based on outdated taxonomy attributing crop losses to Penicillium corymbiferum Westling (a synonym of P. hirsutum Dierkx). The species P. corymbiferum has recently been subdivided into seven taxa which comprise the Pencillium series Corymbifera: P. albocoremium, P. allii, P. hirsutum, P. hordei, P. radicicola, P. tulipae and P. venetum.

Results from pathogencity trials indicated that P. allii was the predominant pathogen of Allium cepa (red onion) and Allium sativum; however it did not infect either tulip or gladiolus. P. hirsutum, P. radicicola, P. tulipae and P. venetum were predominant pathogens of Tulipa gesneriana and P. hirsutum, P. tulipae and P. venetum were predominant pathogens of a Gladiolus sp.

Six of the Corymbifera taxa (excluding P. hordei) caused a rot in the basal root plate of A. cepa (yellow onion); however as P. tulipae produces the mycotoxin penitrem A, which has been previously implicated in tremorgenic toxicosis, spoilage of yellow onion during storage due to this fungus is of particular concern.