Marasmiellus scandens

The most distinctive symptom is the appearance of white, thread-like mycelial strands wrapping around stems and branches.

Infected leaves often turn yellow, wither, and die, remaining attached to the branches by the fungal strands that bind them to the wood.

A thin, whitish film or webbing can be observed on the surface of the bark, which becomes more evident under humid conditions.

Small, white, mushroom-like fruiting bodies may appear on the infected branches, typically in the nodes where leaves were attached.

Branches affected by the disease eventually show signs of necrosis, leading to dieback and loss of the productive canopy structure.

The disease is caused by the fungus Marasmiellus scandens, a member of the Marasmiaceae family that acts as a facultative parasite.

The pathogen is characterized by the formation of white, string-like rhizomorphs that spread across the bark of branches and the leaf surfaces.

Unlike obligate pathogens, it can survive on decaying organic matter before infecting living tissues under favorable environmental conditions.

Dissemination is primarily achieved through the spread of basidiospores by wind or water, as well as the mechanical contact of infected material with healthy parts.

The biology of the fungus allows it to persist on the host plant for extended periods, slowly weakening the tree structure through its superficial growth.

High humidity and consistent moisture levels on plant surfaces are the primary drivers for the growth and colonization of Marasmiellus scandens.

The fungus thrives in dense, shaded plantations where the canopy restricts airflow and prevents the bark from drying out after rainfall.

Temperatures between 22°C and 28°C create the optimal environment for the rapid expansion of the mycelial network across the host plant.

Poor orchard sanitation, such as failing to remove dead wood, allows the fungus to establish a reservoir for ongoing infection.

Cloudy and wet seasons exacerbate the spread of the disease, making it difficult to control without active management interventions.

The primary damage results from the disruption of branch health, leading to the reduction of photosynthetic capacity due to premature leaf drop.

Productivity in cacao and other woody crops is significantly reduced as the tree diverts energy to cope with the fungal presence.

Systemic infections lead to the dieback of major structural branches, which can eventually kill the entire plant if left unmanaged.

Economic losses occur not only through lower yields but also through the increased costs associated with repeated pruning and chemical applications.

The weakened state of infected trees makes them susceptible to other secondary diseases and pests, causing further decline in orchard health.

Pruning is the most effective management practice; infected branches must be removed and destroyed immediately to prevent the spread of mycelia.

Improving orchard ventilation through strategic pruning and canopy management helps reduce the humidity levels that favor fungal growth.

The application of systemic or contact fungicides can be effective if integrated into a regular crop management program during high-risk seasons.

Tools used during pruning must be regularly disinfected to ensure the pathogen is not transferred to healthy trees within the plantation.

Maintaining optimal tree vigor through balanced fertilization and spacing ensures better resistance to the establishment of the fungus.