Mikronegeriaceae

Mikronegeriaceae is a family of microscopic fungi belonging to the order Pucciniales, commonly known as rust fungi. These organisms are obligate biotrophic parasites that derive nutrients exclusively from the living tissues of their host plants through specialized structures called haustoria.

The disease is classified as a rust infection, caused by these fungi forming characteristic sporulation structures within host tissues. As pathogens, they are highly specialized, often targeting specific plant species or genera, which determines the epidemiological pattern and the range of host plants affected.

The host range includes various herbaceous plants, often causing severe damage to legumes and wild grasses. Because they are biotrophic, they do not kill the host tissue immediately, allowing the fungus to continue extracting nutrients while the plant remains alive but progressively weakened.

Symptoms of infection typically include the appearance of small, raised pustules known as sori on leaves and stems. These sori often rupture the epidermis to release powdery spores. Infected plants typically exhibit chlorosis, stunted growth, and premature senescence of foliage, significantly reducing overall crop yield.

Development and spread are favored by high humidity, moderate temperatures, and the presence of surface moisture. Management strategies focus on an integrated approach: using certified disease-free seeds, selecting resistant plant varieties, practicing crop rotation to limit inoculum buildup, and applying systemic fungicides upon the initial observation of pustules.