Regardless of the season there are some foods that are always available and one of them is the banana.
It’s an interesting fruit because of the dominance it has in terms of trade and its unique characteristic of being a non-seed-bearing clone. Most bananas come from Ecuador, Philippines, Costa Rica, Guatemala, Colombia and another 125 other areas. Combined annual global trade in bananas was US$14.7 billion in 2019.
Although the banana has a beautiful and exotic-looking purple bloom, the fruit does not have seed and every banana is a clone of the other. The plants (the banana is actually a herb, not a tree) are propagated with suckers from the corm, which is the rhizome underground. A few suckers may be left on the mother trunk for next year. The fruit starts to mature after nine months and once picked, the main stem dies.
Banana bunches have to be covered and be protected while maturing and then picked while green. Packing is critical to mitigate bruising and storage is almost non-existent at the plantations, so logistics from the fields to transport ships are important.
The world’s eighth-largest crop and the fifth most traded, the commercial banana trade is dominated by one variety — Cavendish (about 40 per cent of production). Cavendish was preceded by Gros Michel which was wiped out in the 1950s by fusarium wilt. Farmers in Canada deal with fusarium wilt in canola, tomatoes, potatoes and cucurbits (commonly known as gourds).
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After the demise of Gros Michel, the Cavendish variety started out being resistant to fusarium. Despite control with up to 50 pesticide and fungicide applications per crop, fusarium is threatening bananas in a serious way with an aggressive variety of fusarium wilt. There are no other non-GMO varieties in the wings for commercial trade.
It is fair to say that the commercial banana trade is a monoculture that is highly vulnerable to disease, even though there are more than 500 cultivars of wild banana (and up to 1,000 when considering plantain). With such a strong focus on the skin of the fruit, which must be visually appealing, there has been little varietal research on commercialization of indigenous varieties.
Indigenous bananas are not as pretty, are small and bruise easily, making them difficult to transport. I have tasted several of these varieties and the tiny fruit is very soft and sweet. Plantain is starchy and less sweet with a thick skin that is often brown or green. This fruit needs to be cooked.
The demand for bananas keeps growing and this results in the continued use of huge amounts of pesticide and fungicide usage as well as the ongoing issues of low prices for farmers, poor wages for workers and human rights violations. As 400 million people depend on bananas as a main source of food there are far-reaching societal consequences to plant disease.
Is one of the solutions biological control?
An example of this is cassava.
I have consumed this heavy, starchy root in many tropical areas around the world. The plant was grown without the use of chemicals until 2008 when mealy bug was introduced and reduced yields by up to 80 per cent. Farmers moved the fields higher into the jungle and the contamination followed. After the introduction of the parasitic wasp, mealy bug stalled out.
With bananas there are fungal solutions that are biologically smart as fusarium likes low pH. Increasing the pH in soil as well as adding lime, zinc sulphate, boron, iron, copper and sodium has reduced fusarium wilt. The greatest advantage though is seen in crop rotation and in particular with Chinese leek. Using Chinese leek in rotation resulted in a reduction of fusarium by 80 per cent and an increase in banana yields by 36 to 86 per cent. Other plants in rotation that also prevent fusarium are pineapple, sugar cane and sunflowers.
To understand the simplistic advantage of rotation and crop diversity, let us look at the gardens of the past.
They were not monocultures. Rows were mixed and flowers were dispersed throughout. The plants varied in colour, height and purpose. While some drew from the soil, others like legumes fixed nitrogen. Rotation in the garden built the soil thus giving it the armour it needed to fight disease. The variety in height and colour confused invaders and they went away in frustration.
As I stood in the plantation where the bananas were rotated with other fruits, I noticed the small irrigation lines at each root and the planting of red peppers to ward off pests. The proud owners were leading change by incorporating biological practices and were on their way to an integrated disease management plan based on fertility and biological control.
All farming today, particularly for those in repetitive monoculture, must consider that unless their industry applies basic principles of natural ecology with biology, diversity, fertility, and incorporate long-term vision — land will continue to tire; farmers will continue to be indebted to chemical control; and crops, all crops including bananas, will remain vulnerable to disease.