Nigrograna

Nigrograna (lat. Nigrograna) is a genus of ascomycetous fungi that includes pathogenic species capable of causing necrotic lesions and rot in various agricultural and ornamental plants. In phytopathology, this fungus is classified as a pathogen responsible for localized tissue damage, often found on weakened or stressed plants.

This pathogen affects a wide range of hosts, including woody species, shrubs, and herbaceous crops. Most frequently, members of this genus are identified on stems, branches, and leaves, where they develop as saprotrophs or weak parasites that thrive when the plant's natural immune system is compromised.

The main symptoms of the infection include the appearance of dark, almost black spots on the affected areas, gradual dieback of bark or leaf tissue, and the formation of the fungus's fruiting bodies (pycnidia or perithecia) appearing as small black dots. These lesions can expand rapidly, leading to the death of individual shoots or entire plant sections.

The development and spread of the disease are directly dependent on air humidity and ambient temperatures. Optimal conditions for infection include prolonged rainfall, high humidity, and the presence of mechanical injuries on the plant, which allow fungal spores to easily penetrate plant tissues.

Control measures involve comprehensive agricultural practices aimed at increasing crop resistance. Recommended strategies include:

• Prompt removal and destruction of infected plant debris.
• Conducting sanitary pruning of damaged branches.
• Maintaining proper irrigation and aeration of planting sites.
• Application of broad-spectrum fungicides upon the first signs of disease spread.