From: Angelina Sanderson Bellamy, Cardiff University, The Ecologist, More from this Affiliate
Published February 8, 2016 07:11 AM

Disease may wipe out the world's bananas

Bananas are at the sharp end of industrial agriculture's chemical war on pests and pathogens, writes Angelina Sanderson Bellamy. But even 60 pesticide sprays a year isn't enough to keep the diseases at bay. It's time to seek new solutions with little or no use of chemicals, working with nature, growing diverse crops on the same land - and breaking the dominance of the banana multinationals.

Herbicides that control weeds are applied up to eight times a year, while bananas may be sprayed with fungicides from a plane more than 50 times per year in order to control Black Sigatoka, an airborne fungus.

Catastrophe is looming for the banana industry.

A new strain has emerged of a soil-borne fungus known as 'Panama disease' which can wipe out entire plantations - and it is rapidly spreading around the world.

Farmers in AustraliaLatin America and across Asia and Africa all fear the worst.

The fungus is almost impossible to stop or eradicate. It moves through soil, so contamination can be as simple as infected dirt travelling from one farm to another on the sole of a shoe, or as complex as soil particles blowing on the wind across long distances - even across oceans, in theory.

Faced with huge losses to a global industry, many have called for a new strain of disease-resistant 'superbanana'. However, this would be just another temporary fix.

After all, the world's most popular banana, the Cavendish, was itself the wonder fruit of its day, being introduced in the 1950s after an earlier strain of Panama disease destroyed its predecessor.

The fungi simply adapted and fought back, though, until the Cavendish also became susceptible. Panama and other diseases will continue to do so until we seriously reform how we grow and market bananas.

Gone bananas

The banana industry is its own worst enemy. The huge farms where most exported bananas are grown are ideal for pests. These plantations are monocultures, which means they grow only bananas and nothing else.

With very few shifts between crops over the years, and lots of tropical sunshine, there is an abundant and year-round supply of food for pests without any breaks, in time or space, to disrupt the supply and lower the disease pressure.

Banana producers spend a third of their income on controlling these pests, according to a study I published in 2013. Chemicals to control microscopic but deadly worms are applied several times a year. Herbicides that control weeds are applied up to eight times a year, while bananas may be sprayed with fungicides from a plane more than 50 times per year in order to control Black Sigatoka, an airborne fungus.

And those bags that are wrapped around each individual banana bunch? They're lined with insecticides to serve as both a physical and chemical barrier to insects feeding on and damaging the skins.

All of this amounts to approximately one litre of active ingredients for every 18.6 kg box of bananas that is exported to consumers in the global north. It's a huge, long-running problem for the industry and the new strain of Panama disease may just be the nail in its coffin.

Or maybe this is the wake-up call the export banana industry so desperately needs.

Searching for the superbanana

Given the way the fungus spreads, containment and quarantine are hardly long-term solutions. Some experts, especially those entrenched in the business of growing export bananas, argue that we need to breed or genetically modify a new type of banana that is resistant to the latest strain of Panama disease.

But this is harder than it sounds. Modern bananas - the tasty yellow ones - don't exist in nature; they were bred into existence around 10,000 years ago. They reproduce asexually, which means they don't have seeds and every banana is a genetic clone of the previous generation.

This lack of genetic variation makes breeding a new banana particularly challenging. If one Cavendish is susceptible to a disease, all others will be too. When all bananas are clones, how do you create the genetic variation from which traits for better disease resistance can be identified and nurtured?

A new banana would also have to be tasty, durable enough to withstand long voyages without bruising, and bright yellow. Looks really do trump pest-resistance. A new type of banana introduced during a previous Panama disease panic back in the 1920s was rejected by consumers for going black on the outside, even when it was ripe and sweet inside.

Continue reading at ENN affiliate, The Ecologist.

Banana image via Shutterstock.

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