Marquandomyces marquandii

Marquandomyces marquandii is a micro-fungus classified as a soil-inhabiting pathogen that typically acts as a facultative parasite. Formerly recognized in scientific literature as Paecilomyces marquandii, this fungus is known for its ability to thrive in various organic environments and potentially affect weakened plant tissues, particularly root systems.

The host range of this pathogen includes a variety of crops, primarily those grown in greenhouses or nurseries. Seedlings and young plants are particularly susceptible to root infections, which can result in significant losses if environmental conditions favor the fungus. The pathogen targets plants that are already struggling with abiotic stress or poor soil conditions.

Symptoms of Marquandomyces marquandii infection include stunted development, chlorosis of the lower leaves, and visible mycelial growth on the substrate surface. Affected root systems often show signs of browning or decay, which prevents the plant from absorbing necessary nutrients and water, eventually leading to permanent wilting or death.

Environmental factors are critical for the spread of this pathogen. High relative humidity and temperatures ranging between 18°C and 25°C provide a favorable environment for sporulation and colonization. The fungus spreads easily through contaminated soil, irrigation water, and even through infested plant debris left in growing containers from previous seasons.

To effectively prevent and control the spread of this fungus, integrated management practices are essential. Growers should prioritize the sterilization of pots and tools, the use of high-quality, pasteurized growing media, and the implementation of strict humidity controls. Biological control agents, particularly beneficial fungi, are highly recommended to balance the soil microbial community and suppress the pathogen.