By MaryAnne Musilo

Elias Gitonga had lost a quarter of his banana plantation to the soil disease Fusarium Wilt before he tried a weed already growing on his farm, Mexican Marigold, and proved the scientists were right, it stops the wilt.

“Farming bananas has been way back since I was a kid. I just inherited from my parents. I mainly plant ripening bananas, but for the past four years I have also been farming plantain due to the high demand. I have planted sweet bananas and the Kampala variety,” said Elias, who farms in Imenti, Meru County.

“In 2020, I started seeing yellowing of leaves in my plants. Some of the plants were showing drought signs, yet I was feeding them adequately. The stem started becoming weak, at times breaking and falling or drying up,” he said.

“In my half-acre where I have planted 200 banana plants, this had affected about 50 of my plants, with 10 plants having reached the advanced stage and dying. I started asking around, since most of my neighbours are banana farmers, and also researched online on the signs I was seeing. This is when I learnt about the fungus and ways to control it,” he said.

For the country’s over 400,000 banana farmers, Fusarium Wilt has been named as one of the crop’s most damaging pests. It stops plants from getting  water and nutrients from the soil, and stays in the soil for decades. 

Across Kenya, virtually every soil now contains fusarium spores, with a study of 1165 soil samples in Taita Tavata finding it in every single sample. But it multiplies most when the soil chemistry is right for it.

Mexican marigold has chemicals that stop the spores from multiplying, reducing the plants affected by 85 to 88 per cent, according to researchers.

Elias had found the science online. “I first pulled up the infected plants, uprooting them and burning them to avoid the spread of the fungus. Then I replanted.”.

“When replanting, I sliced the Mexican marigold in the pit or hole where I was to plant. I also added compost, a generous amount of poultry manure and watered it. I then let it decompose for two weeks and planted my bananas.”

“This method I researched online and because I already had the weed (Mexican marigold), which we normally plant along the fence, I decided to try it out and apparently it worked. The plant growth was good,” he said.

“The sweet bananas and plantain are the most vulnerable to fusarium wilt. The Kampala variety is not much affected,” said Elias. “But I have seen a big improvement and I rarely lose my plants now. Proper feeding of the plant, that is giving manure, and farm hygiene such as weeding, is also important,” he said.

The manure and compost help as fusarium is weaker in healthy soils with the right pH and Elias has also planted Mexican Marigold around his farm to help the soil more.