Fusarium wilt of mulberry

The disease known as Fusarium wilt of mulberry is caused by the pathogenic fungus Fusarium mori. This organism invades the xylem tissues of the plant, blocking the transport of water and nutrients, which inevitably leads to the decline and death of the affected tree.

The primary host for this fungus is the mulberry tree (Morus spp.). The pathogen typically enters the host plant through the root system or through wounds resulting from pruning, frost damage, or pest attacks. Once inside, the mycelium rapidly colonizes the vascular system.

Symptoms of the infection manifest as leaf chlorosis, drooping foliage, and premature defoliation. As the disease progresses, the branches become brittle and die back. When a cross-section of an infected branch is examined, a distinct vascular browning becomes evident, indicating severe systemic damage.

Development and spread of Fusarium mori are favored by high humidity, poor soil drainage, and warm temperatures. The fungus produces survival structures that can persist in the soil for extended periods, making the eradication of the pathogen from an orchard a challenging long-term effort.

Management strategies focus on minimizing infection risk and limiting the spread:

• Pruning and destroying infected branches to reduce inoculum load.
• Sterilizing all pruning tools with alcohol or bleach after each use.
• Improving soil drainage to avoid waterlogged conditions.
• Monitoring trees for signs of stress or damage that could facilitate entry.
• Applying preventive fungicidal treatments and choosing resistant mulberry cultivars.