Panama Disease

External symptoms usually begin with yellowing of the older, lower leaves that progresses upward, followed by wilting and collapse of leaves around the pseudostem, which may split at the base. Cutting the pseudostem or corm reveals reddish-brown to dark discoloration of the vascular strands, the most reliable internal sign. Affected plants gradually decline and die, and disease often spreads outward in patches from initial foci.

Fusarium oxysporum f. sp. cubense survives in soil for many years as durable resting spores (chlamydospores) and on plant debris and alternative hosts. It infects banana roots and grows into the vascular system, where it blocks and discolours the tissue. The fungus spreads mainly through the movement of infected planting material and contaminated soil, water, tools, vehicles, and footwear, which is why biosecurity is central to its management.

• Long-lived chlamydospores allow the fungus to persist in soil for years
• Infection occurs through the roots and colonises the vascular system
• Infected planting material is a primary means of long-distance spread
• Contaminated soil, water, tools, and footwear move the fungus locally

Banana and closely related Musa plants are the hosts of Panama disease. Susceptibility depends strongly on the banana variety and the strain of the fungus: earlier races severely affected some traditional varieties, while Tropical Race 4 affects a much broader range, including Cavendish bananas. Once soil is infested, the disease persists and cannot be eradicated with current methods.

• Presence of the fungus in soil, which persists for many years
• Susceptible banana varieties for the strain present
• Movement of infected suckers, soil, and equipment into clean areas
• Poor drainage and plant stress, which can worsen expression

Because there is no cure once soil is infested and the fungus is long-lived, management centres on preventing introduction and spread through strict biosecurity, using clean planting material, and deploying resistant banana types where they exist. Containment of affected areas is essential.

• Use certified, disease-free planting material such as tissue-cultured plants
• Apply strict biosecurity to clean soil, tools, vehicles, and footwear between areas
• Grow resistant banana types where they are available and suitable
• Contain and isolate infested areas to prevent spread to clean land
• Report suspected Tropical Race 4 to plant-health authorities promptly