Threat against bananas grows

May 19, 2016

“There is a new form of fusarium wilt that is attacking bananas,” the director, National Agriculture Research Laboratories (NARL), Kawanda, Wilberforce Tushemereirwe revealed.

The threat to bananas has continued to grow, following an outbreak of a vicious fungal disease.  

"There is a new form of fusarium wilt that is attacking bananas," the director, National Agriculture Research Laboratories (NARL), Kawanda, Wilberforce Tushemereirwe revealed.

According to online sources, fusarium wilt is a common fungal disease that attacks bananas, potatoes, tomatoes, eggplants and pepper. It enters the roots and interferes with the water conducting vessels of the plant. As the infection spreads to the stems and leaves, it restricts water flow, causing the foliage to wilt and turn yellow.

The new strain is more vicious than the previous fusarium wilt, Tushemereirwe explained. "It started in Asia, but has now reached Mozambique," he said. He was, however, quick to point out that researchers in Uganda are working round the clock to find a solution before the disease gets here.     

"We have produced varieties that are resistant to both the Banana Bacterial Wilt and the old fusarium wilt, so we are doing research against the new fusarium wilt," he said.

The annual domestic banana consumption in Uganda stands at 220-460kg per person. "It is the staple food for 13 million people and important source of nutrition, and provides income security for smallholder producers," says Dr Jerome Kubiriba, head of the banana programme at Kawanda. He adds that banana growers in Uganda consume about 75% of the crop harvested in their homesteads.

"The total annual value of bananas grown in Uganda is $530m (about sh1.6 trillion). This value can be improved, for instance, if the country fights against the banana bacteria wilt," he says.

If there is effective control of pests and diseases such as banana bacterial wilt, coupled with improved soil fertility, high soil water conservation, use of improved varieties, Kubiriba says banana production can improve by about 40%, thus increased revenue.

"For instance, banana productivity is about six tonnes per hectare, about 20 tonnes per hectare in Ankole and about 60 tonnes per hectare at Kawanda. With improved practices, the Buganda farmer can reach 20 tonnes and the Ankole farmer can reach 60 tonnes. Still that would leave a gap of 40 tonnes," he explains.

He says that if wilts are controlled effectively for about a year, productivity can double, for instance, from five clusters a bunch to eleven.  Looking at food security he says at least 17 million Ugandans depend on bananas for food and income.

Symptoms of fusarium wilt in bananas

Wilting and a light yellow colouring of the lower leaves, most prominent around the margins. They eventually turn a bright yellow colour with dead leaf margins.

As the disease advances, more of the leaves become yellow and die. A "skirt" of dead leaves often surrounds the pseudo-stem. In the advanced stages of disease, affected plants may have a spiky appearance due to prominent upright apical leaves in contrast to the skirt of dead lower leaves

Online sources

How to grow bananas

Clear the site of bushes and trees

Bananas require large planting holes. They must be at least 3x3feet wide and  two feet deep.

Remove the soil from the sucker and cut off the roots. Cut off the bottom of the corm so that it is flat. Cut off the top as well.
   
When planting, the top of the corm (sucker) should be one inch below the surface of the soil.
   
Dig water trenches in the shamba. These help control soil erosion. The trench should at least be about 2ft wide and 1 foot deep.
   
Mulch the plantation to retain moisture in the soil; the deeper the mulch, the better the soil moisture retention.
   
Restrict the number of suckers around each plant to three (i.e mother, daughter and granddaughter) to limit competition.
   
Weeds compete with bananas for water and nutrients and so they should be removed.

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