Fusicoccum putrefaciens

Fusicoccum putrefaciens is a fungal pathogen belonging to the Helotiaceae family, often associated with its teleomorph, Godronia cassandrae. It is a significant concern in horticulture, specifically impacting berry-producing crops. This pathogen is known for causing localized tissue death and systemic decline in susceptible plants.

The primary hosts of this pathogen include cranberry and highbush blueberry. The disease manifests as stem cankers, branch dieback, and fruit rot. In cranberries, the pathogen is a major cause of "end rot," which significantly reduces the shelf life and quality of harvested fruit, making it a critical issue for commercial fruit supply chains.

The life cycle of Fusicoccum putrefaciens involves the production of asexual spores (conidia) and sexual spores (ascospores). These spores serve as primary inoculum and are disseminated by splashing water, rain, and wind. The fungus overwinters in infected twigs and leaf litter, re-emerging in early spring to infect new vegetative growth or developing berries.

Disease progression is highly dependent on environmental factors, particularly moisture and temperature. Cool, wet springs combined with high humidity create optimal conditions for fungal sporulation and infection. Inadequate site drainage and poor canopy aeration significantly increase the risk of an outbreak, as they keep foliage wet for longer durations.

Controlling this pathogen requires an integrated pest management (IPM) approach. Essential strategies include rigorous sanitation, such as the pruning and removal of infected wood, and maintaining adequate plant spacing to facilitate airflow. Additionally, the strategic application of protective fungicides during bloom and pre-harvest intervals is often necessary to minimize crop losses.