A banana affected by the disease
The Ministry of Agriculture through National Agricultural Research Organisation (NARO) has prescribed emergency and quick remedies for the fight against a new disease that is wiping out plantations in Uganda and neighbouring Rwanda.
By the end of June, the disease was reportedly present in 60 per cent of the plantations in South Western Uganda and Northern Rwanda. According to the Ministry, however, similar signs were first seen in 2017 in the country, but they disappeared following intense rains later that year before resurfacing in 2019.
However, the farmers said the intensity of the fruit discolouration increased when the rains became heavy between September 2019 and January 2020. Early this year, an aggressive wave broke out and this time, it is spreading faster than previously. Some farmers in Busoga have reported similar signs in their plantations, and claim it could be an effect of sugarcane growing.
“…We are facing a problem of this unidentified disease which comes as a result of planting bananas on land which previously had sugarcane. We are seeking help. The banana fingers become brown and hard to peel when attacked,” says Jonah Suubi, a farmer in Jinja, Eastern Uganda.
A team of researchers from the National Agricultural Research Organisation, Operation Wealth Creation and the Ministry of Agriculture has been in Southwestern Uganda on a fact-finding mission and are yet to tell what the disease is. However, they concluded that it is caused by grasshopper-like pests called rust thrips that feed on the green skin of the developing banana fruits causing them to scar, stain, and even get deformed.
“They are small yellow insects with narrow fringed wings. The insect’s attack by feeding on the green surface of the banana fingers. The bananas appear brown, purplish to black. The discolouration however is on the surface of the fruit peel,” says the NARO research team. But the banana fruit is ultimately destroyed when fungus seeps through the scar to the inside of the fruit.
“The scars provide an opening for opportunistic fungi including disease-causing ones, especially anthracnose that take advantage and creep into the affected areas. In extreme cases of severely affected fruits, the whole bunch appears blemish,” the researchers say, adding that often the symptoms do not manifest until after two months as the fruits begin to mature.
For now, in Uganda, the epicentre of the disease is in Greater Mbarara’s 11 districts including Mbarara, Ibanda, Isingiro, Kazo, Mitooma, Rwampara and Sheema. According to the extension workers and the NARO scientists’ observation on the farms across sub-counties in Isingiro district, the incidence varies from 3 per cent to 90 per cent of farms and even bunches affected.
The Chairman of Rugaga Farmers Market, in Bukanga Sub- County, Isingiro District, Hussein Sebanakita says the daily sales out of the market were 30,000 bunches, but due to the effect of the damage to the fruits, they now send out less than 25,000 bunches per day. But he adds that the prices of the affected bunches have greatly dropped because buyers reject them.
As a result, commercial farmers have had to destroy their bunches since traders refuse to pay for them. The thrips causing the observed symptoms are transmitted through infected planting materials, according to the experts, as well as the using the traditional cleaning and mulching methods.
“In already infected plantations management practices including cutting old leaves and de-trashing within the same field aid the spread of thrips,” they say, but add that there are some simple solutions mainly stopping the multiplication of the thrips, which can help.
“Immediately at flowering, use recommend commercial clear polythene bags of 0.08mm thickness that is perforated at 76mm interval with holes of 12. 7mm to cover the bunch as it opens.”
They also advise the farmers to cut down the affected banana fruits and bury them to reduce the population of the insects in the field and also destroy the neglected or abandoned plantations as these can serve as a ground for thrips to multiply.