As rains end a long, dry spell in Kenya, a new threat is emerging to food security. Experts have warned that green maize for roasting, a delicacy for many Kenyans, could contribute to the spread of the deadly armyworm if moved from the counties where the pest has been reported to areas where it has not invaded.
These counties include Baringo, Bungoma, Busia, Kakamega, Kericho, Nakuru, Nandi, Trans Nzoia and Uasin Gishu.
“Movement of infested plant materials, such as green or dry fodder for animals or green maize cobs, can aid in carrying the different armyworm stages in the same farm or in the locality,” the team wrote in a statement.
“In Kenya, long-distance movement of green maize for roasting is a thriving business, which can contribute to the spread of the pest.”
The team is derived from six institutions, including the Kenya Agricultural Livestock Research Organisation.
OUTBREAK ALERT
On March 23, the government issued an alert on the outbreak of the fall armyworm to all county directors of agriculture in the nine western and Rift Valley counties affected. Some counties in the Coast region like Kwale have also reported the outbreak.
Agriculture CS Willy Bett last week led experts to the Rift Valley region to assess the situation and also educate farmers on preventive measures.
“We will be sensitising farmers on weed spraying, as that is the best preventive measure. The fall armyworm (FAW) is not a normal worm and has to be sprayed in the evening when it comes out to attack the crop,” Bett said while briefing the media on the national food situation.
He added that the occurrence of this pest in the western region — the grain basket of the country — poses a major threat.
Fall armyworm, Bett said, is a ferocious feeder. The pest population build-up is rapid, as one female lays 1,500 to 2,000 eggs in her lifetime usually in batches of 200 eggs on a single plant.
“Once we have visited and analysed the situation, we will set up a fund to buy chemicals for farmers, as the worm can completely destroy the maize crop, and this could affect our next long-rains harvest,” the CS said.
SPREAD IN AFRICA
Kalro director general Dr Eliud Kireger says the relatively new pest is native to the western hemisphere — from the US to Argentina. In Africa, the fall armyworm was first reported in September last year in the West Africa region. It has now been reported in Central, Southern and East African regions where it is rapidly spreading and causing huge crop losses. A field survey carried out last month by the team of experts first observed irrigated maize crop in Trans Nzoia county during an off-season. The experts say all the maize growing agro-ecologies in Kenya are potentially at risk because the armyworm moths can fly over large distances of nearly 100km a day or night. “The pest is spreading rapidly and can cause 100 per cent loss in a wide range of crops, such as maize, rice, pasture, sorghum, millet, cotton and some vegetables. This will hurt national food security and lead to loss of income unless urgent measures are implemented,” Kireger said.
He added that the pest occurs in large numbers and its larvae (caterpillars) cause severe damage to more than 80 plant species, including maize, sorghum, rice, millet, wheat and barley. It also attacks fodder grasses such as Bermuda grass and napier grass, sugar cane and cotton.
“However, fall armyworm has only been seen to attack maize in Kenya,” Kireger said.
The director general said attack on young maize can reduce plant density, which calls for re-planting. Moreover, infestation on grain in the cob exposes the crop to fungal attack.
ECONOMIC BURDEN
Dr Stephen Mugo, a maize breeder from the International Maize and Wheat Improvement Centre (CIMMYT), said the damage in Kenya can only be estimated at the end of the current cropping season. However, some countries in Africa have already reported serious damage and crop loss.
“The costs to control the FAW in Brazil was estimated to exceed $600 million annually (Sh60 billion). In Zambia, the government has already spent $3 million (Sh300 million) in an attempt to control the pest. However, the full extent of the damage in the affected countries due to FAW is yet to be established,” he said.
He says the damage on maize may be observed on all plant parts depending on developmental stage, and that the decision on pest control against FAW depends on various factors, including level and stage of pest infestation and cost (affordability) of the control options.
“CIMMYT recommends an Integrated Pest Management is the best possible solution to effectively tackle the pest in both the short- and long-term. ” he explained.
“This includes chemical control, biopesticide, biological control, host plant resistance (through conventional or transgenic breeding) and agronomic management (early planting and intercropping with compatible crops that are less affected by FAW).”
Mugo says farmers should avoid late planting to avoid peak immigration of adults, monitor the presence of the insect-pest systematically and periodically in the field and take control measures if the pest symptoms are identified on 10 per cent of plants.
He adds that: “Farmers should also remove and destroy all crop residues after harvest, deep-plough the soil to bury the larvae and the pupae if any, regularly weed the field and the surroundings and ensure optimum fertilisation in the crop.”
Kireger says studies on the management of fall armyworm in Kenya have not been undertaken, so the multi-institutional consortium is using information based on publications from other countries to make posters and brochures for communication to farmers, extension staff and the general public.
Farmers are encouraged to scout for signs and symptoms of the pest, starting one week after crop germination.
PREVIOUS THREATS
For the last couple of years, Kenya has experienced outbreaks of pests and diseases, particularly on the maize crop. In August last year, the government confirmed an outbreak of head smut disease, which affected maize in Nandi, Elgeyo Marakwet, Trans Nzoia, and Uasin Gishu counties.
Agriculture PS Richard Lesiyampe said investigations revealed the disease was prevalent in the fields where crops were exposed to stress.
Farmers were encouraged to practice crop rotation to break the cycle of the disease and to burn the affected crops.
This came after a repeated outbreak of the deadly maize lethal necrosis disease, which affected more than 49,421 acres of maize worth Sh2 billion in 2013. Farmers were advised to uproot the affected crops.
Researchers have so far been able to establish four maize varieties tolerant to the maize lethal disease, though it is yet to be released to farmers.