Wangeci Kinyua farms rice on 4 acres in the Mwea rice irrigation scheme. [Gardy Chacha/Standard]
Mwea rice farmers grapple with apple snail invasion
Smart Harvest
By
Jane W Mugambi
| Aug 09, 2025
Rice farmers in the Mwea Irrigation Scheme, Kirinyaga County, Kenya’s rice production hub, have been struggling with golden apple snails (Pomacea canaliculata) devastating crops since 2018.
Despite government promises through the Ministry of Agriculture for a lasting solution, the pests threaten rice yields critical to national food security.
Joseph Kamau, a Tebere Section Four farmer, said government-supplied pesticides have failed.
“We need a more effective pesticide,” he urged.
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Drying farms to starve snails, as suggested, is ineffective, as irrigation resumes for planting, creating breeding grounds. “The cycle persists,” Kamau noted.
Peter Njogu from Wamumu reported the snails’ rapid spread, destroying rice despite chemical sprays.
“We’ve tried everything, even hand-picking snails and eggs, but it’s an uphill task,” Kamau added.
Farmers hired workers and used tobacco products, yet the pests proliferate despite government-recommended chemicals.
In 2023, the government launched Biograde 330 SL to curb the infestation, but farmers like Stanley Irungu say it’s ineffective.
“We adopted Biograde fully, but we’re back to square one,” Irungu said.
Desperate, some farmers now buy unregistered, potentially dangerous chemicals from Uganda to protect nursery crops, risking health and environmental harm.
Kirinyaga County Deputy Speaker Jinaro Njamumo, also Mutithi Ward MCA, warned of rising cancer cases linked to harmful pesticides and damage to irrigation canals.
“Avoid unverified chemicals and exploitative brokers,” he cautioned, noting high cancer rates tied to pesticide use. “Farmers must not be experimental objects,” he added.
The snail invasion threatens Mwea’s rice output, with losses up to 14 per cent. Farmers urge the government to research sustainable solutions, like biological controls, to eradicate the pests and protect livelihoods.
The apple snail, introduced to Africa through contaminated planting materials, causes yield losses of up to 14 per cent and net income reductions of 60 per cent in moderately infested areas, with severe cases seeing 50-80 per cent crop damage.
If unchecked, the pest could spread to other rice-growing regions like Ahero, potentially causing regional losses of $67-116 million (Sh8.66 billion to Sh14.99 billion) annually.
Farmers are calling for urgent government action, including rigorous research into sustainable solutions like biological controls—such as introducing ducks, which have proven effective in Asia by feeding on snails without harming rice—and stricter quarantine measures to prevent further spread through machinery and seeds.
The Kenya Plant Health Inspectorate Service (KEPHIS) and CABI recommend integrated pest management, combining physical removal, cultural practices, and farmer training.
With Mwea’s rice critical to Kenya’s economy, immediate action is essential to protect farmers and ensure food security.
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