Macrophomina

Macrophomina is a genus of fungi that includes important plant pathogens. The most well-known species is Macrophomina phaseolina, which causes charcoal rot in a wide range of agricultural crops worldwide. This fungus is a facultative parasite, meaning it can survive on dead organic matter in the soil as well as infect living plants. It is characterized by the production of small, black, sclerotia, which are hardened masses of fungal hyphae that serve as survival structures and are responsible for the "charcoal" appearance of infected tissues.

Macrophomina phaseolina thrives in warm and dry conditions, making it particularly problematic in semi-arid and tropical regions. Its disease cycle typically involves the sclerotia overwintering in the soil. When favorable conditions arise, these sclerotia germinate and produce conidia, which are the asexual spores that infect plant roots and stems. The pathogen can spread through infected seeds, soil, and plant debris. Symptoms of charcoal rot include wilting, stunting, leaf yellowing, and eventually, the death of the plant. Within the infected plant tissues, characteristic black sclerotia develop, often visible on the surface of roots, stems, and fruits.

Management of Macrophomina infections relies on a combination of strategies. Crop rotation with non-host species can help reduce the inoculum levels in the soil. The use of resistant crop varieties is also an important control measure. Maintaining good soil health, including adequate moisture and nutrient levels, can help plants better withstand infection. Fungicides can be used, particularly as seed treatments, to protect young seedlings. Early detection and removal of infected plant material are also crucial for preventing further spread.