Fall Armyworm attack: Uganda’s concerted efforts at curbing infestation

The spread of FAW is alarmingly high in Uganda but the African country is also looking at every possible solution to fight the infestation

By Lominda Afedraru
Published: Tuesday 12 March 2019
A field infested with the pest. Photo: Lominda Afedraru

In the early morning of November 2017, I arrived on the farm of Mary Yangi, who in 2016 trekked a long journey from South Sudan to Uganda’s West Nile region to settle as a refugee.

Yangi, a few months later settled into farming unlike others, who were reliant on food rations from the United Nations High Commission for Refugees. The 59-year-old widow saw an opportunity when she settled in Ngurua village in Arua district.

The jolly lady who befriended native Ugandans came out of her grass thatched hut with a maize field surrounding the house. “You know when one is watching news on television or reading about the plight of refugees from South Sudan, the common thing you will see is families leading a difficult life. But coming from a family that treasured farming, I had to do what is right,” Yangi said.

But Yangi and other maize farmers in the region are struggling to deal with the fall armyworm (FAW) invasion. Part of her small farm is some 200 meters away and infested with the pest. “Back home we used to grow a lot of maize and we experienced no insect infestation which is a different case here in Uganda,” she said.

She said scientists from Abi Zonal Agricultural Research and Development Institute (Abi ZARDI) in Arua have visited on a number of occasions, advising farmers to spray a chemical called rocket to eliminate the FAW infestation from their farms.

The team also promised that in the near future farmers will be given maize varieties that resist FAW, something scientists are working on.

FAW has been ravaging maize fields in Africa since 2016 with the first incidences reported in Southern Africa countries. In East Africa it was first reported in western Kenya by farmers in March 2017 and immediately confirmed by the Kenya Plant Health Inspectorate Service and Kenya Agricultural and Livestock Research Organisation.

It immediately spread to the neighboring countries of Uganda, Burundi, Ethiopia and Rwanda raising alarm amongst policy makers. In Uganda the Ministry of Agriculture advised farmers to use rocket to spray their farms. Towards the end of last year the incidence of the pest was reducing but it has since sprung and farmers are in a dilemma on what to do next.

Currently over 30 countries have identified the pest within their borders including the island countries of Cape Verde, Madagascar, São Tomé and Príncipe and the Seychelles. FAW type introduced into Africa is the haplotype originating from south Florida, USA and the Caribbean.

The pest is capable of feeding on over 80 different crop species making it one of the most damaging crop pest. Some of the crops include maize, sorghum, rice, sugarcane, cabbage, groundnut, soybean, onion, cotton, pasture grasses, millets, tomato, potato and cotton.

How FAW behaves

The FAW moths have both a migratory habit and a more localised dispersal habit. It can migrate over 500 km before positioning to settle in one place. When the wind pattern is right, moths can move much larger distances of 1,600 km. The pest is capable of persisting throughout the year.

The Director General National Agricultural Research Organistaion, Ambrose Agona, explains some of the long- and short-term measures farmers in Uganda can adopt in a bid to prevent the pest from infesting their fields.

He notes that FAW exited farmer fields in the US in 1797. It is still new in Africa and this means stakeholders have to adopt some of the ways of managing it from countries that have experienced it before.

Armyworm species

There are a number of species of armyworm caterpillars, many with a distinct taste for a particular plant or vegetable. Some will eat anything green. They’re attack at night and hide in plants and under garden debris during the day.

They attack the crop at their larval stage sometimes moving in masses to new areas in search of food. In Uganda the attack is mostly aerial, with the gray moths usually arriving under cover of darkness to lay eggs on leaves of maize in farmer fields.

In dry season the larvae stay close to the ground feeding on grass species but in rainy season when farmers have planted their maize, they move up to feed on the leaves and fresh maize cob causing 100 per cent yield loss.

Agona explains that there is a programme involving scientists in research institutes sensitising farmers on what to do. The Ministry of Agriculture is also collaborating with Food and Agriculture Organization in curbing the destruction.

Using sex pheromone traps

Farmers have been advised to erect pheromone traps near fields to trap adult male moths. A pheromone is a chemical secreted by a female insect to attract males for mating and once the male insects are trapped in the bucket there is no more possibility of mating.

It is important to establish it in one month before planting the crop and the trap is placed next to the maize field so that the scent of the pheromone is carried across the top of the plants by the wind and they should be hanged on poles. It is replaced every four weeks for continuous trap process and trapped insects must be removed every week.

Use of natural predators

Farmers are advised to avoid using harmful pesticides or practices that would inadvertently destroy beneficial insects. Some bird species especially soldier birds are good at consuming the fall armyworm and farmers are advised not to scare away birds seen in search of pests in their farms.

Farmers are expected to spray the field with insecticides such as Garden Dust, Monterey Garden and Rocket. They must use selective and biological pesticide containing Bacillus thuringiensis to control leaf eating caterpillars and FAW.

FAW in tropical climates completes its life cycle in 30-40 days and farmers are expected to avoid treating successive generations of the pest with the same active ingredient.

Other preventive methods

Farmers have been sensitised to use natural horticultural oil spray, an example is multipurpose neem oil spray at various stages of larvae growth.

Scientists recommend intercropping maize with drought-resistant Greenleaf disodium and planting Brachiaria Mulato II grass on the farm’s edge to help curb the pest. The leguminous Greenleaf desmodium becomes repellent, emitting a blend of compounds that help push fall armyworms away from maize while Brachiaria Mulato II grass produces chemicals attractive to the pests.

FAO has introduced Fall Armyworm Monitoring and Early Warning System App for farmers to check their crops for infestation which they can upload and the data is validated. Once a farmer checks their crops for infestation, they can upload the required data on the App, it is sent to national fall armyworm focal points and transferred to a global web-based platform.

Fall Armyworm Task Force Coordinator Regina Eddy was quoted in media in 2018 saying the worm has damaged about 3 million hectares of maize crop so far. Additionally, agriculture experts estimate the pest has caused over US $13 billion in losses for crops across African countries.

As for Uganda the Commissioner of Crop Protection at the Ministry of Agriculture states that although the country registered bumper maize harvest during the first season last year, more than half was lost to the fall armyworm.

The statistics from the ministry compiled jointly with FAO indicates that by mid-2017 the worm was present in all 127 districts of Uganda causing 15-75% crop loss.

An estimated figure of 450,000 tonnes of maize, equivalent to US $192 million was lost during the first cropping season of 2017 affecting 3.6 million people.  

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