Bananas and their industry
Bananas are one of the cheapest and most consumed fruits around the world. In fact, they are the fourth most commonly traded agricultural product.
According to FAO, and based on 2016 export figures, the global banana industry generates around USD 8 billion per year. Some 15% of this production is destined for international trade, whereas the rest is an important staple food for developing countries.
The production of bananas for this international trade is concentrated in a small number of countries mainly located in the tropical regions of Latin America, Africa and Asia, and in the European Union (French Caribbean islands, Canary Islands). For these countries, banana production and export represent an important source of revenue and employment. For example, according to the Martinique prefect in the french caribbean islands, the banana industry is the largest private employer, with a total of 10.000 direct and indirect jobs (over a total population of 800.000). For Ecuador, the world top exporter of bananas , the banana industry represents 26% of the country’s agricultural gross domestic product.
Indeed, banana cultivation is just the first step of a chain of tasks that ends with bananas being sold to international consumers. When they are exported, bananas are harvested while still green. At the packhouse they are inspected and sorted for export. Fruits are then transported to ports to be packed in refrigerated ships called reefers. In order to prevent their maturation during transport, they are stored at a temperature of 13.3°C, and require careful handling in order to prevent damage. When bananas arrive at their destination they are first ripened in special ripening rooms , then dispatched to shops for final sale to consumers. Each of these tasks provides employement and generates income.
Black sigatoka, a threat for bananas
Black Sigatoka or Black Leaf Streak Disease (BLSD) is one of the most economically important threat for banana growers. This disease is caused by a fungus (Mycosphaerella fijensis) which affects leaves thereby decreasing the photosynthetic surface of the plant. This alone can reduce yields by up to 50%.
In addition, fruit produced on heavily diseased plants can show a significant reduction in « green life » span. For export, this constitutes a problem as fruits ripen prematurely during shipment and are lost before being sold. Most areas of the tropics and subtropics are affected, with reported losses of 30-50%.
This relatively recent disease is now responsible of intensive fungicide application in producing countries. As the most exported banana cultivar in the world « Cavendish » is very susceptible to Sigatoka , this disease understandably represents a major threat. The risk is two-fold : a poor disease management leads to yield losses and increases production costs, and non optimal product application can have negative impacts on human and environmental health. In both cases poor disease management leads to economic loss and impacts producing countries.
The warning system
In order to help growers fight black Sigatoka, different warning systems have been developed since the seventies in the Antilles and Cameroon. These systems, originally tailored for the less virulent yellow Sigatoka, have been recently adapted by the researchers of CIRAD (the french institution research leader in tropical agronomy) to black Sigatoka. They are based on an early detection of attacks, which are monitored regularly and used to calculate indicators quantifying the development of the epidemic. In Martinique these indicators have become a crucial support to the phytosanitary strategy. Cercoban, the plant protection unit affiliated to Banamart (the producers cooperative of Martinique), can count on a network of technicians that are constantly monitoring banana grows all over the island. Observed symptoms are evaluated, classified and then transformed into scores used to issue warnings to growers when risk is high. Symptoms are classified according to a severity category, with the help of a visual key. Severity scores are then used to calculate a set of indicators that can be interpreted to evaluate the global severity and the speed of disease spread.
Thanks to this system, products are now applied at the right time for maximum efficacy and Martinique has been able to respect new laws limiting fungicide use while maintaining high banana yields.
ITK and CIRAD make growers life easier with Sigatocare, an application against Sigatoka disease
ITK has recently responded to CIRAD’s request and digitalized their warning system: a new application for desktop and smartphone has automated the calculation of indicators and made observation recording easier. Technicians and banana growers are now able to record observations directly on their smartphone in the field. Data are immediately saved on remote servers and indicators are returned automatically without need of transcription or hand-made calculations.
Moreover, Sigatocare app provides a new type of indicator, which integrates those classically calculated by CIRAD and their dynamics over time, to evaluate the necessity of phytosanitary applications in the coming days. It is expressed according to a colour key (red : high risk, yellow : medium risk, green : low risk). In order to develop it, ITK has formalised CIRAD’s expert reasoning behind the issuing of phytosanitary warnings. This expertise has now been automated and makes decisions even easier and more efficient. The new synergy between CIRAD and ITK is good news for the banana world. It is a further step in the direction of a better and safer phytosanitary strategy which will protect bananas and their environment.
Agronomist and scientific editor