Lethal maize disease spread by soil - experts

RESEARCHER: Dr Stephen Mugo
RESEARCHER: Dr Stephen Mugo

Seed experts have said there is a possibility that the maize lethal necrosis virus, which destroyed hundreds of hectares of maize last year, could be spread through the soil.

Dr Stephen Mugo, a maize breeder and the International Maize and Wheat Improvement Centre Africa regional representative, said this could further complicate the fight against the deadly disease which destroys 300,000 metric tonnes of maize yield in Kenya yearly.

“This will be a bigger challenge to farmers as they could experience more losses. They now must embrace crop rotation and use certified seed varieties,” Mugo said.

Previously, experts said the disease only came from infected seeds, which would have been easy to control.

So far four hybrid maize seed varieties that are tolerant to MLN have been released from the ongoing examination at the screening facility at Karlo-Naivasha.

CIMMYT maize programme director Dr B Prasanna said there are fears that the disease is spreading rapidly and that unless urgent measures are taken, it could go out of control.

“The disease is a regional problem, having been reported in Kenya as well as in neighboring countries — DR Congo, Ethiopia, Rwanda, Tanzania, South Sudan and Uganda where maize is also a staple food,” he said during a maize disease forum organised by the Alliance for a Green Revolution in Africa, the Bill & Melinda Gates Foundation, CIMMYT in collaboration with the Kenya Agricultural and Livestock Research Organisation.

More than 150 maize breeders, scientists, policy makers, seed companies and regulators met in Nairobi last week to take stock of current knowledge and best practice in managing maize lethal necrosis.

Investigations by Karlo revealed that MLN is caused by a mixed infection of two viruses namely, the sugar cane mosaic virus and maize chlorotic mottle virus, which are known to be seed transmitted.

Sugar mosaic virus has been prevalent in many parts of the country affecting cereals but MCMV was reported as a new virus in Kenya.

Mugo said countries like the USA that have been able to fight the disease made it through combination of using tolerant varieties, crop rotation, strict surveillance where the affected crops were destroyed and having maize free periods (where farmers agree on a period when there is no maize in the fields so that the insect vector which transmits the disease dies).

“We do not have maize free periods but eventually farmers in Kenya will have to go this way. They can agree as a community to have periods where they do not plant maize to fight the disease. No country has fought the disease with one hammer,” he said.

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