Control Methods for Penicillium Rot of Lily Bulbs

Symptoms: Occurs during storage. The lesions on the bulbs are sunken, dark brown, and covered with a blue-green mold layer (spore masses). The inner scales gradually rot, eventually causing dry rot of the bulb. Generally, it takes two to three months for the bulb to completely rot.

Pathogen: Penicillium cyclopium Westl., a fungus belonging to Deuteromycotina, Hyphomycetales, Penicillium, Penicillium cyclopium. Colonies are dark blue-green, with no concentric rings or indistinct rings, granular or clustered, with a pale pinkish reverse, occasionally yellow or with a purple tinge. Conidiophores are 3 to 3.5 micrometres in diameter, with penicilli of three whorls, 3 to 3.5 micrometres in diameter; phialides are 7 to 10 x 2.5 micrometres. Conidia are subspherical, smooth or slightly rough, 3 to 4 micrometres in diameter. In addition, P. corymbiferum Westendorp also damages lilies.

Disease conditions: Bulb injury, damp storage areas and poor ventilation easily lead to infection and damage by Penicillium.

Transmission route: This fungus is distributed in the air and soil. If the pathogen adheres to the surface of the bulbs, it will multiply massively upon exposure to high temperature and high humidity. The disease can occur during the harvesting, packaging and transport of the bulbs. The pathogen invades through wounds.