Blue mold

Systematic position and nature of the pathogen
Blue mold (Penicillium glaucum) belongs to the kingdom Fungi and the genus Penicillium. It is a microscopic mold fungus that typically functions as a saprotroph, but under specific environmental conditions, it can act as a facultative parasite, causing various types of rot in agricultural crops.

Diseases and affected crops
This pathogen is primarily responsible for penicillium rot in fruits, vegetables, and seeds. The main targets for this fungus include bulbs of ornamental and vegetable crops, root vegetables (beets, carrots), tomatoes, apples, and stored grains. A characteristic sign of infection is the development of a moldy bloom, which eventually turns a gray-blue or glaucous color.

Biology and life cycle
The fungus reproduces asexually through conidia, which are dispersed by air currents, water, or insect vectors. The mycelium penetrates plant tissues through mechanical injuries, skin cracks, or natural pores. During its life cycle, Penicillium glaucum secretes enzymes that break down plant cell walls, leading to tissue softening and the rapid progression of rot.

Conditions for development and spread
Optimal conditions for the rapid development of the pathogen include high relative humidity (above 85%) and moderate temperatures ranging from +15°C to +25°C. However, the fungus can also thrive at lower temperatures, making it a severe pest in storage facilities, warehouses, and crop storage units with poor ventilation systems.

Damage and control measures
The economic impact results in the total loss of produce marketability and the rapid decay of entire harvests during storage. Key control measures include:

• Practicing crop rotation and thorough removal of plant debris from fields.
• Maintaining optimal temperature and humidity levels in storage facilities.
• Using high-quality, undamaged planting materials.
• Sanitizing crates and storage areas with fungicides before loading the harvest.
• Performing timely sorting and culling of infected fruits.