Mortierellosis

These microorganisms are primarily saprotrophic, meaning they decompose organic matter in the soil; however, under specific conditions, they become facultative parasites.

Fungi of the genus Mortierella produce an extensive mycelium network that colonizes the root system, hindering nutrient absorption and water uptake.

They possess a remarkable ability to survive in unfavorable environmental conditions by forming resilient resting spores that persist in the soil for years.

The development of the pathogen is typically triggered by root exudates, which provide the necessary nutrients for the fungus to thrive in the rhizosphere.

The primary symptom of infection is stunted growth, often misdiagnosed as nutrient deficiency or drought stress by growers.

The root system of infected plants turns brownish and becomes soft, with significant decay observed in smaller feeder roots.

In humid conditions, a characteristic white or grayish mycelial mat may appear at the base of the stem or around the root collar.

Leaves often begin to yellow from the bottom up, leading to premature wilting and reduced plant vigor even when water is readily available.

• Stunted vegetation development
• Darkening and softening of root tissues
• Visible white mycelium on the stem base
• Premature chlorosis and leaf wilting
• Decay of fine root hairs

Waterlogged soil conditions are the most critical factor promoting the development and spread of mortierellosis in agricultural fields.

High levels of undecomposed organic matter in the soil serve as a primary substrate for the multiplication of these fungi.

Moderate temperatures ranging from +15 to +22 degrees Celsius are optimal for the growth of mycelium and the germination of fungal spores.

Soil compaction and poor aeration exacerbate the disease by creating an oxygen-depleted environment that stresses the plant roots.

Monoculture practices significantly increase the inoculum density, making the soil increasingly prone to subsequent outbreaks of the disease.

The disease leads to substantial yield losses due to impaired root functionality, which reduces the plant's ability to assimilate minerals and moisture.

Compromised root health makes plants highly susceptible to secondary bacterial and fungal infections, often causing total crop collapse.

The commercial quality of the final harvest is diminished, resulting in smaller, underdeveloped produce that lacks market value.

Economic impact is significant, often necessitating costly soil amendments, chemical treatments, or the complete abandonment of the infected crop.

Long-term infestation of the soil complicates agricultural planning, as many common rotation crops may also be susceptible to the infection.

A well-planned crop rotation is the most effective cultural practice to disrupt the life cycle of the pathogen and reduce soil inoculum.

Proper soil management, including the improvement of drainage and aeration, is essential to prevent the waterlogged conditions that favor fungal growth.

The use of high-quality seed treatments with broad-spectrum fungicides can protect the developing root system during the critical germination phase.

Incorporating biological control agents such as Trichoderma species helps maintain a healthy rhizosphere and outcompetes the pathogenic fungi.

Regular field monitoring and immediate removal of infected debris are necessary to minimize the spread of spores throughout the production area.