Armyworm complicates East Africa’s food security calculations


This foreign pest has just invaded Kenyan farms, and nobody knows what to do about it. Tighten your belt, it’s about to get messy.

Monday May 08 2017

One uneventful afternoon in March this year, insects expert Muo Kasina was enjoying a cold glass of pina colada when he received a call from a small-scale farmer in Kitale, Trans-Nzoia County.

’Must be another worm attack, he thought to himself. He was right. And also wrong. Terribly wrong.

As the farmer described the damage insects had inflicted on his maize plantation — there was nothing that could be salvaged — Dr Kasina’s eyes began to widen as the pina colada lost its attraction.

Damn, I hope it is not the fall armyworm, he thought to himself, again. I hope.

Suddenly, the mind of the entomologist, who is also the director of National Sericulture Research Centre at Kenya Agricultural and Livestock Research Organisation (Kalro), wandered into the Bible story of the plagues that God sent to wipe out Egyptian farms.

But the insect in Kitale was worse than the locusts of Egypt. It was the dreaded fall armyworm, and it had the potential to drive an entire nation into hunger and famine. Before arriving in Kenya, it had ravaged over 300,000 hectares of food crop in southern Africa. Dr Kasina, therefore, had every reason to lose appetite for his rum, pineapple juice and coconut cocktail.

He asked research officers in Kitale to look into the matter, and as they visited farms, he consulted regional and international crop experts. Every one of them, down to the last call and e-mail, told him to prepare for the worst.

“This was the first time the fall armyworm was being detected in Kenya,” he told HealthNation recently, “and nobody knew what to do about it.”

The Food and Agriculture Organisation of the United Nations (FAO) says the worm, native to the Americas since 1957, has ravaged Brazil for decades, but no one knows how it crossed the seas to Africa. A few researchers hypothesise that it could have been shipped here alongside maize supplies.

The International Maize and Wheat Improvement Center suggests that it first landed in Nigeria in January last year. From there, it made its way into central and west Africa before burrowing into southern Africa at the start of this year. It arrived in Kenya in March.

And so, barely a year on the continent, the fall armyworm has lived up to its fame. The FAO indicates that Zambia has lost 90,000 hectares of crop, while Malawi and Zimbabwe have lost 17,000 and 130,000 hectares, respectively.

FAO’s Africa coordinator David Phiri is now worried about the food security of the continent because all the countries that the insect has attacked so far are Africa’s key producers of maize, the staple food of more than 80 million people on the continent.

As at April 28, 2017, fall armyworm invasions had been confirmed in 14 other countries, including the whole of East Africa.

The invasions are particularly painful for the region, as they come at a time when the Greater Horn of Africa — Djibouti, Eritrea, Ethiopia, Kenya, Somalia, South Sudan, Sudan and Uganda — is being ravaged by a famine that the United Nations has termed as “the worst in three decades”.

In Kenya, panicky technocrats and researchers met to form a technical working team comprising experts from Kalro, Center for Agricultural and Biosciences International (Cabi), pesticide manufacturers, Kenya Plant Health Inspectorate Services (Kephis) and the Ministry of Agriculture, Livestock and Fisheries.

Their assessment of the damage so far showed that Kenya has lost approximately 15,000 ha of maize, valued at Sh1.3 billion. The annual loss could be 40 million bags of maize, valued at Sh120 billion, assuming that the cost of one bag remains at Sh3,000. That loss is exclusive of the cost of farm inputs, including seeds, fertiliser, irrigation, pesticides, and labour.


Armyworm attack: Agriculture Cabinet Secretary Willy Bett (centre), when he toured some of the maize farms affected by the fall armyworm invasion in Kinyoro, Kitale, Trans Nzoia County, on April 8, 2017. PHOTO | JARED NYATAYA


Mr Joseph Ng’etich, director of Crop Resource and Plant Protection at the Ministry of Agriculture, says the counties affected by the worm so far are Bungoma, Busia, Siaya and Kisumu in the western region; Trans-Nzoia — which hosts the maize belt of Kitale, Uasin-Gishu, Kericho, Nandi, Bomet, and Narok in the south Rift; and West Pokot in the north Rift. Others are Baringo and Nakuru in central Rift, and Kwale in the Coast. Last week, Kalro confirmed that the insect had invaded Kiambu.

United in their disdain for the fall armyworm, globally acclaimed agriculture experts gathered in Nairobi at the end of last month to understand its biology. They wanted to track its behavioural ecology — how it feeds, how it reproduces, and what chemicals affect it the most.

Prof Ken Wilson of Lancaster University in the UK said even the insect’s life cycle differentiates it from those that Kenya is used to, such as the African armyworm, a less destructive species that feeds exclusively on maize, wheat, sorghum, rice and pasture grasses, unlike the fall armyworm, which has a voracious appetite and feeds on more than 80 varieties of crops.

Even worse, at the larva stage, the fall armyworm is a cannibal, feeding on other larvae, meaning at maturation it colonises huge swathes of land. Other insects have a life span of between two to six months, and are thus vulnerable to predators and pesticides. The fall armyworm, on the other hand, is not loyal to the natural laws of food-chain dynamics. It reproduces fast, and dies even faster, at the age of two weeks.

“It is new here, so even the mites and spiders have not learnt how to eat it,” said Dr Kasina, of Kalro. “And by the time they do, it will have had its fill and moved on.”

It is also a very fertile insect, laying up to 2,000 eggs within four days in batches of 100 to 200 on immature maize plants. It eats up the leaves — the food-making part of the plant involved in photosynthesis — leaving the plant stunted and unproductive.

This larval destruction takes 14 to 28 days, after which the pest climbs down from the dead plant to the soil to become a pupa, a process that takes seven to 10 days.

Then it becomes a moth, the final product in a series of vampirism cycles on a farm. The moth, a strong flier that can cover up to 100 kilometres a day, lives for about 11 to 14 days.

During this time, the army of moths disperse in the hunt for something else to devour. The spread is as wide geographically as is the intensity in each farm.

The government says its only hope in fighting the worm is in pesticides, and the Ministry of Agriculture says it requires an additional Sh320 million for this. The ministry’s Joseph Ng’etich says the money will be used for training of extension officers, the public and purchase of pesticides.

“Before we know what to do in the long term, we have to slow down its reproduction as quickly as possible,” Ng’etich told HealthyNation.

However, experts have raised environmental concerns over the use of pesticides in this scale, and Mr Ramasany Srinivasan, an entomologist from World Vegetable Centre in Taiwan, says “the pest will develop resistance to available pesticides if application is not managed and guided”.

These concerns are valid as, Dr Kasina says, farmers sprayed double or triple the recommended dose in the hope that they could eradicate the pest faster. 



Now that it is here, it is not going anywhere 

Apart from its agility, the fall armyworm thrives in any temperature above 10 degrees Celsius. That is basically anywhere in Africa.

Staring in the eye of a new threat to the country’s agricultural survival, experts in Kenya have to learn as quickly as possible from other countries that have battled the pest, as well as apply control measures that have been used successfully on other crops in the country.

Small-scale farmers, who contribute 70 per cent of agricultural production in Kenya, according to Food and Agriculture Organisation (FAO) estimates, hold the key to the success of the war on fall armyworms. But even then, Mr Boddupalli Maruthi Prasanna, director of the Global Maize Programme at the International Maize and Wheat Improvement Center (CIMMYT) and the CGIAR Research Programme on Maize, says “we cannot eliminate the pest from Africa”.

“Now that it’s here, it will stay,” he says. “But we can provide support to farmers and provide options to manage their crops against it.”

Dr Muo Kasina says any strategy should limit damage to the environment and costs as much as possible, and that includes using pesticides judiciously. Small-scale farmers, for instance, can pick the insects from their crops or pour ash or fine soil on them.

“They have a soft, delicate skin that would be pricked by the ash,” he says.

In large-scale farms, Dr Kasina advises that the government deploys the military or the National Youth Service. To pick the worm, however, farmers have to differentiate it from its cousin, the African armyworm. Major markers include the fact that it does not move in colonies, its fully grown larva has a set of four dots on the end of the abdomen that look little black bumps that make a square, and it also has an inverted Y on the head capsule and white stripes just behind the head.



Intercropping: Intercropping with legumes has been used as an effective control method. In Nicaragua, for instance, it reduced infestation by 30 per cent in 1981. The cassava plant has also been cited in studies as immune to the pest’s appetite because of the cyanide the plant produces.

Biological warfare: In 2013, Kalro used pheromones — a chemical produced by an insect to modify how members of its species relate to it — to reduce sandflies, which had so ravaged Kenya’s avocado crop that South Africa banned it. “The female pest produces chemicals to attract the males,” explains Dr Muo Kasina. “We harvest that chemical and make synthetic forms of it, which we place in farms. The males are attracted to the trap and are killed en masse. When all the males are decimated, the pest will not reproduce, and so it dies off.”

Genetic engineering: The United States has managed to resist massive fall armyworm losses by planting genetically modified maize, but the jury is still out on the use of genetic material in Kenya.