Solution to controlling Panama disease in bananas

In a bid to find solutions and share experiences in controlling the Panama Fusarium wilt epidemic in banana plants, on December 13th in Ho Chi Minh City, the Department of Plant Production and Protection, in coordination with the Vietnam Agriculture and Nature Newspaper and the Fruit and Vegetable Research Institute, organized the Forum 'Solutions for Preventing and Controlling Fusarium Wilt in Bananas'.

Sharing an overview of the Philippine banana industry, Dr. Mary Grace B. Saldajeno, an expert from Dole Corporation, stated that the country ranks fourth globally in fresh banana exports, with Cavendish banana growing areas concentrated primarily on Mindanao Island. Banana Fusarium wilt (Panama disease) began appearing in the country in the early 2000s, was officially recorded in 2005, and spread rapidly during the 2010-2015 period, causing significant damage to key banana production areas.

The causative agent of the disease is the fungus Fusarium oxysporum f. sp. cubense (Foc), which can persist long-term in the soil, has high genetic diversity, and is very difficult to control. The disease manifests through yellowing and wilting of leaves, splitting of the pseudostem, and discoloration of the vascular system inside the plant. It spreads mainly through infected planting materials (suckers), soil, irrigation water, farming tools, and other intermediate hosts.

Particularly worrisome is the TR4 fungal strain, because this strain not only harms the Cavendish variety but also affects many other banana cultivars. Current control measures for TR4 are very limited, as once the fungus is established in the soil, it is nearly impossible to eliminate completely. Meanwhile, up to now, no banana variety suitable enough to replace Cavendish on a commercial scale has been found.

At Dole Philippines, Fusarium wilt was officially recorded in 2008. By 2012, the number of diseased plants recorded periodically was about 10,000. This number continued to increase sharply, reaching its highest level by the end of 2018, with approximately 60,000 cases across all Dole branches in the Philippines.

In response to this situation, Dole developed and implemented an integrated Fusarium wilt management system. First and foremost are prevention and eradication solutions, where the early identification of infected plants is considered key, requiring thorough training for technical teams and workers on symptom recognition. Diseased plants must be completely uprooted and destroyed.

In parallel, the company uses disease-free planting material propagated by tissue culture and strictly adheres to quarantine and biosecurity measures to prevent the introduction and spread of the TR4 fungal strain.

Regarding cultivation practices, Dole focuses on utilizing banana lines with resistance, which are developed through somaclonal variation, natural selection, accelerated hybridization, or induced mutation. Field sanitation and water management are also emphasized, particularly digging ditches and drainage channels in areas prone to waterlogging.

Furthermore, the use of organic mulching materials and inhibitory compost helps improve the soil microbiome, creating a healthier and more diverse soil environment. Mechanical and physical measures are applied concurrently, including disinfecting farming tools and equipment, installing foot wash pools, wheel sterilization baths for vehicles, and control checkpoints within the biosecurity system. The removal and destruction of infected plants are carried out as a mandatory sanitation measure to limit the source of infection.

"In terms of biological control, we supplement with beneficial microorganisms to inhibit pathogens and stimulate plant growth, utilizing inhibitory compost and commercial biological products. Chemical intervention plays only a supporting role and is used very sparingly, primarily through disinfectants for sanitation and biosecurity, or soil amendments to adjust pH, creating unfavorable conditions for the TR4 fungus.

Several new commercial active ingredients are also being evaluated for their potential against this fungal strain. The entire disease management process is based on monitoring and data-driven decision-making. Regular field surveys are conducted, diseased plants are recorded and sampled for testing, which then informs the selection of appropriate interventions and determines the most effective time for application," she stated.

Sharing insights on the global trend of developing disease-resistant banana varieties, Dr. Mary Grace B. Saldajeno stated that somaclonal variation has been introduced into production with a moderate level of tolerance. Other methods include conventional breeding, natural selection, mutation induction through gamma irradiation, accelerated hybridization, and gene editing, which are currently in the testing phase and preparing to complete regulatory approval procedures.

Among these, gene editing is considered a major breakthrough in crop breeding. This technology allows for the purposeful modification of DNA sequences or gene activity without introducing foreign genes into the plant, aiming to improve nutrition, flavor, and increase resistance to diseases and adaptation to climate change. Compared to traditional genetic modification, gene editing offers a faster development speed and has gained broader acceptance in more countries.

Nevertheless, current disease-resistant banana varieties still face significant limitations. Many varieties only possess tolerance and have not yet reached complete immunity, and the effectiveness of their resistance heavily depends on specific conditions such as pathogen density, climate, and soil type. Furthermore, market acceptance remains a major challenge, as farmers and exporters require products that meet requirements for flavor, ripening characteristics, and transportability within the supply chain. Issues concerning regulatory frameworks and public perception of gene-edited bananas also vary among countries. Finally, the sustainability of resistance is always an open question, as pathogens can adapt, and relying on a single gene or strategy poses a long-term risk of failure.