Written by Sarah Ooko
Threats to food security by disease out brakes are not new to East Africa; neither is it about to end if reports by farmers are anything to go by. A sustainable solution to this challenge however lies in crop diversity. Yet in East Africa, farmers are yet to move away from over-dependence on maize as their staple food with devastating consequences due to a scourge of a fatal disease dubbed Maize Lethal Necrosis in East Africa.
Just like most East Africans, Caroline Samoei in Kenya's Bomet County relies on maize farming as a source of food and income for her family. But she is now worried. "In 2011, a strange disease attacked my crops and I harvested only half a sac from an acre of land. My kids almost slept hungry,” says Ms. Samoei.
A year later, she decided to try again. "I sold three cows and used the proceeds to plant maize in five more acres. But as soon as they began flowering, the disease hit again. Without any gains, I am no longer motivated to farm yet it is my life," says a frustrated Ms. Samoei, widow and mother of two children.
Her cries echo that of many farmers enduring the scourge of a fatal disease dubbed Maize Lethal Necrosis (MLN) in East Africa. The disease, first spotted in Kenya, has since been reported in Tanzania and Uganda. "And the issue is, how far will it go this year? That’s why we need to urgently look for a solution," notes Dr. Ephraim Mukisira, Director of the Kenya Agricultural Research Institute (KARI).
Since maize is a staple crop for most East Africans, experts note that MLN poses serious threats to the region's food security. “It will also affect our economy since maize is a source of cash for farmers and export revenue for the country,” says Dr. Godfrey Asea, a Maize Breeder at the National Crops Resources Research Institute (NaCCRI) in Uganda.
Threats to food security by disease out brakes are not new to East Africa; neither is it about to end if reports by farmers are anything to go by. Dr. Mukisira notes that a sustainable solution to this challenge lies in crop diversity. He notes that “we need to move away from overdependence of maize as our staple food," he says.
"So as we address this problem of MLN, we are also advising farmers to plant alternative food crops such cassavas, sweet potatoes and others not affected by the disease," says Kheri Kitenge, Maize Breeder at Selian Agricultural Research Institute in Tanzania (SARI).
Dr. Mukisira notes that these crops will cushion farmers from food shortages and give them alternative income sources.
Dr. Anne Wangai, Chief Research Officer and MLN expert from KARI notes that the disease is spread by insects such beetles and thrips. "Upon feeding on infected plants, they pick the disease and transmit it to other crops they fly off to or the winds blow them to."
She adds that reports from other countries where the disease previously existed - such as Texas, Argentina and China- indicate that transmission can also be through seeds but in very low rates (about 0.005 percent). “We are yet to determine if that's the case here."
To prevent and manage MLN infection, Dr. Wangai calls on farmers to apply good agronomic practises such as using fertilisers and buying seeds from certified sellers. She notes that they should also practise crop rotation. "Where maize was previously planted, have another crop from a different family."
Dr. Asea states that early planting should be encouraged since pests tend to move from older to younger plants with more sup. Indeed, he notes that field observations in Uganda showed that MLN infections were severe in later planted maize crops.
Farmers are advised to plant maize at the onset of main rainy seasons and not during the short rain periods. This creates a break in planting seasons and reduces the populations of pests that spread MLN.
Dr. Wangai notes that symptoms of MLN include yellow patches on otherwise green maize leaves, dwarf plants and combs with very few or no grain fillings. “Farmers should immediately uproot infected plants to prevent further transmission."
Dr. Wangai states that crops from infected maize fields should not be moved to other areas. "They can be fed to animals or turned to silage". She however warns that rotten combs and grains with mold are not safe for animal or human consumption, and should be destroyed immediately.
Dr. Wangai advises farmers to watch out for scrupulous sellers out to exploit them by selling pesticides that are supposedly effective against MLN. "Chemical control does not work with this disease. And since symptoms often appear ten days after infection has occurred, spraying afterwards serves no purpose," she says.
Amidst the MLN menace, rays of hope still exist for farmers. The International Centre for Wheat and Maize Research (CIMMYT) is currently testing maize varieties from affected regions and other world nations." We want to determine which ones are resistant to the disease then we will release them to farmers," says Dr. Dan Makumbi, Maize Breeder at CIMMYT.
Based on field observations, researchers have already noted some progress. Instead of being totally wiped out, some maize varieties are already showing some tolerance against MLN
Dr. Wangai notes that MLN was first reported in the United States of America in the 1970 s "but scientists took aggressive measures and developed resistant seed varieties for farmers". She says that "we still need to do our own trials as the virus we have here is slightly different and environmental conditions differ from America."
She notes that seeds resistance to MLN will eliminate the yield loss problem and provide a long term solution for Maize farmers.
According to Dr. Wangai, MLN occurs when maize is infected by two pathogens: Maize Chlorotic Mottle Virus (MCMV) and Sugarcane Mosaic Virus (SCMV).