Colectivelly nominated the 10th staple food of the world, banana and plantain (the starchy relative of banana, staple food in many poorer comunities in the Third World) are quite susceptible to pests and diseases. International banana trade relies almost exclusively on one type, the Cavendish sub-group. This cultivar amounts for almost 80 % of all banana exports, which was selected for taste but also for durable long-distance international transport.
Whilst most pests gain resistance to plant defense mechanisms in time, Cavendish bananas do not have the geene pool to allow them to keep on top of that. What’s worse, pests also gain resistance to pesticides.
Towards the end of 2013, IBIS has picked up an increased number of alerts and articles from the web, which pointed to the fact that there is an unusual high number of issues affecting the banana crops. Amongst them, Black Sigatoka disease ( produced by Mycosphaerella fijiensis), The Panama Disease (produced by Fusarium oxysporum, scale insects and milibugs which are vectors of transmission for these diseases.
In December 2013, Costa Rica (the world’s 10 banana exporter) declared a phytosanitary emergency, which will last a year, to combat the pests transmitting Black Sigatoka. Another fungus, Fusarium oxysporum f. sp. cubense, which is deadly to Cavendish, has reached plants in Mozambique and Jordan. Until now it has only affected crops in Southeast Asia and Australia. (Specifically Taiwan, Indonesia, Malaysia, the Philippines, and China.). According to the journal Nature, this is a reason of worry, being the first intercontinental spread report. Researchers fear the fungus will soon reach Latin America, which grows the majority of the world’s bananas. Some sources indicate also that the recent events could have also been triggered by the climate change.
Whilst scientists are trying to engineer bananas with superior pest and disease resistance (including the Gros Michael variety) little progress has been made as yet. However the losses seem to have stirred the international world. Currently, world’s biggest banana producer is India, followed by Latin America, which also dominates the international trade.
Will 2014 see a decline in the production of banana? How will this affect the world trade?
Monocultures offer the perfect conditions for the spreading of pests and diseases. In this respect, bananas are no different from any other crop.
Back in the 50s, the most common banana variety, Gros Michel, was completely wiped-out by what was known as Panama disease. This disease was caused by the fungus Fusarium oxysporum, also called fusarium wilt. Gros Michel was replaced by a resistant southern Chinese variety called Cavendish.
For the last thirty years a new disease has been becoming more and more widespread. The disease is called Black Sigatoka. Right now, the only way to treat this new disease is by applying massive doses of fungicides – a practice which is losing effectiveness as the fungus is becoming more resistant. In several regions the disease can cut banana yield in half, leading farmers to spray their plantations up to fifty times a year. This practice endangers the environment and the health of plantation workers.
Black Sigatoka isn’t only threatening the Cavendish bananas that are popular in Europe and North America. It also affects local varieties that are popular in Asia, Africa and Latin America. These include starchy plantains, prepared similarly to potatoes, which are a staple food in many poorer communities in the Third World.
Disease defence: Bananas lack genetic diversity
Monocultures and Black Sigatoka aren’t the only reasons why bananas are in trouble. Cultivated bananas are known as pathenocarpic, which means they can form fruit without ever having been fertilised. Rather than forming seeds, bananas reproduce by forming side-shoots and suckers. This means that the gene pool of bananas never really changes over the generations. This is a major restriction to breeding possibilities: all efforts to introduce fungus resistance to Cavendish bananas through conventional breeding methods have failed.
Many banana producers hope to save Cavendish bananas with the help of genetic engineering. This technique could finally be able to provide popular Cavendish bananas with resistance to Black Sigatoka.
What happened to the previous cultivar, the “Gros Michel” banana type
“A strain of the Fusarium oxysporum fungus was responsible for the demise of the precursor to the Cavendish, the Gros Michel banana. The Gros Michel was the main type of banana imported into the U.S. from the 19th century through the 1950s, when the fungus struck. Gros Michel has been described as tastier than the beloved Cavendish, but most present-day fruit lovers have never tasted of its glory. ” http://planthealth.org/article/prepare-yourself-bananapocalypse-yahoo-news.
The new threat: Black Sigatoka
Black Sigatoka is a disease affecting banana and plantain crops. It spread from Asia and reached the Carribean in 1991. The Food and Agriculture Organisation (FAO) has warned that without increased commitment to combat Black Sigatoka Disease, which has ravaged banana and plantain production in the Caribbean, vulnerable people could face food insecurity if the disease situation is allowed to further deteriorate.
This is all the more important since banana producing countries are facing another threat: a new strain of Panama disease – Tropical Race 4. It was originally confined to East Asia, but recently there have been reports that it has been found on a banana farm in Jordan and a banana farm in Mozambique. In both cases, authorities say the disease has been isolated. It is suspected that it could spread further and eventually reach Latin America and the Caribbean just like many other diseases have done in the past.
Black Sigatoka does particularly well in hot and humid climates and often spreads due to informal trade among the islands. The disease first appears as narrow streaks and black spots, which, as they proliferate, can eventually blacken entire leaves of bananas and plantains, blocking photosynthesis. Banana bunches are smaller, as are the fruit, and due to premature ripening that can occur even while the fruit is still on the tree, the bananas are no longer suitable for export.
Costa Rica Emergency (2013)
Bananas are an important part of the country’s agricultural business, which makes the pest problem such a big deal. In fact, the Agriculture and Livestock Ministry’s State Phytosanitary Services recently declared a national emergency for Costa Rica’s most important export.
According to The Tico Times, folks who make their living growing bananas are presently squaring off against legions of “mealybugs and scale insects” that are effectively destroying their crops. Since the pesky invaders cause unsightly blemishes to appear on bananas, some importers might turn their noses up at the goods.
Costa Rica has declared a state of phytosanitary emergency in response to a spread of pest populations that is threatening the country’s banana farms. The Ministry of Agriculture’s State Phytosanitary Service (SFE) said Boisduval scale and banana mealybugs infestations affected 24,000ha of plantations in the country’s Atlantic region from Talamanca to Sarapiqui.
Although the damage inflicted by these pests is largely cosmetic, resulting in spots on the banana fingers, growers fear their fruit will be rejected in packhouses.
“The biggest risk is that our exports will be restricted, shipments returned and markets closed, which will have serious repercussions on the industry and affect the country’s commercial standing,” SFE service director Magda González said.
The state of emergency, which will last for a year, allows the authorities to increase imports of bags of Bifenthrin and Buprofezin which help manage the effects of the infestation. The mitigation strategy also includes integrated management and biological pest control measures, SFE said.
a workshop will be held in Davao City, Philippines, on February 6-7 (Thu.-Fri.), 2014, on the theme, “Can the spread of Panama disease in banana be managed? Finding multi-level solutions for a global problem”. The workshop will bring together people from the private and public sectors, farmers’ organisations and nongovernment organisations, and research institutions.
Some experts have blamed climate change, with warmer temperatures and changing rain patterns, for the explosion in the bug population.
Magda Gonzalez from Costa Rica’s Phytosanitary Service told Reuters up to 20 percent of Costa Rica’s banana crop could be affected.
“At the moment, the problem that we have is that the two plagues are distributed practically across the entire (agricultural) sector where there is banana. That’s one thing. This started as a little point in La Estrella Valley and from there they dispersed towards other areas. At the moment, it’s said that suppliers could reject 20% of the fruit,” she said.