Neofusicoccum macroclavatum

Neofusicoccum macroclavatum is a fungal pathogen classified within the Dothideomycetes class and the Botryosphaeriaceae family. As a significant agent of plant disease, it is known to cause botryosphaeria-related infections in a variety of woody hosts. It acts as both an endophyte and a pathogen, waiting for host plant stress to initiate severe disease symptoms.

This pathogen primarily targets various fruit-bearing trees and specific forest species, including eucalyptus. The infection typically manifests as bark necrosis, the formation of cankers on stems and branches, and eventual dieback of foliage. In some instances, the fungus can also cause fruit rot, which is a major concern during post-harvest storage.

The life cycle of the pathogen revolves around the formation of pycnidia, which produce conidia as asexual spores. These spores are dispersed primarily by rainfall and wind to new infection sites. The fungus typically enters the plant host through wounds in the bark caused by pruning, insects, or environmental stress, where it then colonizes the xylem and phloem tissues.

The development of the disease is highly favored by warm temperatures and periods of high humidity. Environmental conditions that place the plant under water stress or heat stress significantly increase the susceptibility of the host to infection. In such conditions, the fungus can spread rapidly throughout the orchard, increasing the incidence of symptomatic branches.

The economic impact of the pathogen is marked by yield loss and reduced tree longevity. Effective management focuses on cultural practices:

• Regular pruning of infected branches to reduce inoculum.
• Sterilization of pruning tools to prevent mechanical transmission.
• Irrigation management to avoid plant stress.
• Application of targeted fungicides when environmental conditions favor spore dispersal.