Marasmius rot

Marasmius rot is a fungal disease caused by various species of the Marasmius genus. It is classified as a necrotrophic pathogen that affects the structural integrity of plant tissues. This disease is particularly concerning in tropical agriculture, where high humidity levels create an environment conducive to the rapid spread of the fungus.

The pathogen is well-known for its destructive impact on Indian mango (Mangifera indica). It primarily targets fruits, leading to significant post-harvest losses. While it most commonly affects fruits, under favorable conditions, the infection can also spread to twigs and leaves, causing dieback and reducing the overall vitality of the host tree.

The characteristic symptoms of Marasmius rot include the development of water-soaked, brownish lesions that expand rapidly across the fruit surface. As the infection progresses, a white to grayish mycelial mat often forms over the affected area. In advanced stages, the fruit tissue softens, decays, and may eventually turn into a shriveled, mummified structure.

The development and dissemination of the disease are heavily dependent on environmental factors, specifically high relative humidity and moderate temperatures. The fungus typically survives as mycelium or rhizomorphs in plant debris or on infected branches. Rain splashes and wind are the primary vectors for the movement of spores, facilitating the rapid colonization of healthy fruit in an orchard.

Effective management requires a multi-faceted approach. Cultural practices such as pruning to improve canopy airflow are essential to reduce humidity around the fruit. Furthermore, strict sanitation—removing all fallen and infected fruit from the orchard—is critical to lower the inoculum levels. Preventive fungicide sprays during critical development stages can help protect the crop and ensure sustainable production.