Can Organic Farming Prevent TR4 Banana Disease?

Is organic farming the solution to the devastating banana disease called TR4?

TR4 is killing banana crops around the world

A new release from the United Nations’ Food and Agriculture Organization (FAO) has announced that the TR4 fungus that is decimating banana crops throughout Asia and the Middle East may spread to tropical producers, leading to the potential destruction of banana production throughout the world.

The fungus is called Fusarium oxysporum f.sp. cubense and while some have compared it to Panama disease as it also strikes the roots – it is not Panama disease.

Bananas are the 8th most important global food. And only about 15% of it is shipped outside of its country of origin. This means that it is still largely a local food that feeds many people in poorer countries.

The FAO estimates that about 17 million metric tones are traded, but 130 metric tones are produced.

Bananas are also one of the most nutritious foods. High in potassium and fructooligosaccharides, it is an important food for our probiotic populations. Its content of B vitamins, vitamin C and three grams of dietary fiber make it a necessary food for nourishment.

Earlier races of fungi have destroyed some varieties

Two earlier strains (actually called races) have destroyed other banana varieties: notably race 1 and race 2 of the fungi. The Cavendish banana has been resistant to these previous races, but now the fourth race – Tropical Race 4 or TR4 – threatens the Cavendish banana as well.

The spread of the fungus to South American and other tropical producers could devastate the world production of bananas. Bananas are produced in 135 countries, mostly by smaller local growers. But the fungus has been known to infect the soils and it is thus easily transmittable by those who travel from producer to producer.

The fungus has a number of vectors of infection. It can spread via dirt (soil on the shoes) and moisture. When it finds its way to the roots of the banana tree, the fungus will destroy the tree from within.

Currently there is no known fungicide that will kill the fungus. And the fungus will remain in the soil for decades. And there is no currently-known species that will resist the fungus.

Is organic farming the solution?

The only solution the FAO can offer is quarantine. This means segregation of banana plantations from each other. This might be compared to making everyone stay at home if there was a flu virus going around.

In what circumstance could a banana plantation remain isolated from other plantations?

About the only viable means is through the organic industry. The organic industry is founded upon the principle of isolation – at least from conventionally-grown crops that can spread their pesticides and chemical fertilizers onto neighboring farms. Organic growers must remain isolated from conventional farms in order to keep their farms certified.

In conventional farming, pesticide and fertilizer application will often be done by large scale contractors who travel from plantation to plantation with their chemical wares.

While this doesn’t mean organic banana farms do not share the risk of acquiring the fungus – they may be less susceptible due to their current isolation from conventional farming practices.

And because organic banana plantations are typically smaller than conventional plantations, their ability to isolate their production from other banana producers is one of the hallmarks of organic production in this age of chemical farming.

And because of their size, organic farms are better able to respond and switch plant varieties easily – to varieties that may resist the fungus.

Soil in organic farms may also provide some resistance. This was shown in a study from the University of Florida. Researchers tested the soils of organic and conventional tomato plants with two Salmonella species of bacteria, and found the organic soil resisted the spreading of the bacteria significantly more than the conventional soil of the tomato plants.

Organic hygiene

Organic farmers are also more focused upon hygiene than conventional farmers. Because organic farmers must prevent the infection of their crops by numerous pests (including fungi) without the use of chemicals, they typically maintain cleaner conditions surrounding their plants when compared to conventional farmers. This is because many pests spread from rotting limbs and the like.

Conventional farming techniques also have another weakness in that they typically utilize monoculture: They use the same strains and hybrids over and over. This decreases their long-term resistance to particular pests like fungi and others because those pests can adapt and focus their energies upon a single strain of the crop.

Nature does things differently. Nature will naturally develop hybrids that will be resistant to emerging diseases. This is because nature is smart.

While there is no conclusive evidence that organic banana trees are resistant to the fungus, there is clear proof that organic crops have shown stronger immunity to a range of pests.

Crown rust in oats provides example

This proved to be the case of crown rust disease in oats. Crown rust is caused by the infection of a fungi classified as Puccinia coronata. The fungi will cause orange spotting on the plant and seed. It has damaged thousands of acres of oat crops over the past few decades.

Yet research from the USDA Agricultural Research Service established that organic oats had a greater resistance to crown rust.

The reality is that organic crops have a greater resistance to fungi and other pests. This is often a matter of the organic plant being better nourished by the wider variety of nutrients available from natural composted fertilizers.

Studies from India have found that fungicide applications have led to an increased infection rate among conventional crops. The research by the Indian Council of Agricultural Research states:

“Systemic application of fungicides has led to pesticide resistance and resurgence of other diseases.”

Supporting organic means buying organic

By supporting organic farmers that maintain better plantation hygiene and support the natural immunity of the plant, we stand a better chance of surviving the coming devastation to our banana crops.

Is there any proof that organic bananas will resist the TR4 fungi? No. Only time will tell.

But we do know that organic bananas have survived evolving fungi and other pests for millions of years. Yet we find only now bananas face a virtual extinction from this fungi – after only a few decades of chemical and monoculture farming. Coincidence?

In the meantime, organic growers we talked to are looking into planting different varieties.

Monoculture is certainly a clear factor with the TR4 fungi – as previous races were not capable of infecting the Cavendish. The fungi species has adapted to the monoculture strategy of conventional banana growers. It has become capable of infecting a plant that was previously resistant to it.

REFERENCES:

World Banana Forum. Tropical Race 4 (TR4) of Fusarium wilt (Fusarium oxysporum f.sp. cubense): Expanded Threat to Global Banana Production

OAT QUALITY IMPROVEMENT FOR FOOD, FEED, AND VALUE-ADDED APPLICATIONS.

Gu G, Cevallos-Cevallos JM, Vallad GE, van Bruggen AH. Organically managed soils reduce internal colonization of tomato plants by Salmonella enterica serovar Typhimurium. Phytopathology. 2013 Apr;103(4):381-8. doi: 10.1094/PHYTO-04-12-0072-FI.

Doehlert, D.C., McMullen, M.S., and Hammond, J.J. Genotypic and environmental effects on grain yield and quality of oat grown in North Dakota. Crop Science. 2001. v. 41. p. 1066-1072.

Disease Control in Organic Crops.