Lethal maize disease spreads into Uganda

Saturday March 30 2013

A deadly maize disease that was first reported in Kenya and Tanzania has spread to Uganda, raising food security concerns.

The Ministry of Agriculture warned that Maize Lethal Necrosis (MLN) had been reported in some districts in eastern Uganda, particularly Busia and Tororo.

The disease, scientists say, can cause up to 100 per cent crop loss. It is suspected to be spread by beetles, thrips and leaf hoppers.

“Uganda scientists are working in collaboration with International Maize and Wheat Improvement Centre to find solutions to the disease,” said Agriculture Research Organisation spokesman Robert Anguzo.

The International Maize and Wheat Improvement Centre is also working with the Kenya Agricultural Research Institute (Kari) to develop maize varieties that are resistant to the disease.

READ: EA scientists fighting maize disease


MLN attacks all maize varieties.

Staple food

Uganda is the only East African country that produces more maize than it consumes. But the threat from the disease means that any further spread will affect the region’s food security, particularly in Kenya, where maize is a staple food.

Uganda produces about 2.7 million tonnes of maize a year against a demand of 1.5 million tonnes. The surplus is sold to South Sudan, Tanzania and Kenya.

The disease is caused by two viruses: The sugarcane mosaic virus and maize chlorotic mottle virus. Although each virus can infect maize separately causing a different problem, when they occur together in the same plant, they cause MLN.

The disease presents itself as severe chlorosis (yellowing of leaves), vein banding and mottling of the leaves and cobs, which lead to premature drying of the crop, even in plants that appear to have no disease symptoms.

No pollen

In addition, there is failure to tassel (sterility) in male plants as there is no pollen shed on grains.

Necrosis and leaf redding may also be observed in some plants.

Kari first reported the disease in September 2011 in Kenya’s Bomet County in South Rift Valley. By mid last year, the disease had spread to Narok and Naivasha areas.

In Tanzania, the disease was reported in Mwanza.

Agricultural officials fear that production volumes will dwindle if the disease is not checked.

To break the disease cycle, farmers have been advised to practise crop rotation and ensure they skip planting maize for at least a year.

They have also been warned not to replant seeds from the previous harvest to help reduce the vector population.

Other measures recommended include weed control to eliminate the vector hosts, proper use of fertiliser and use of high quality seeds to boost production.