Battling the Bugs: Kenya’s 10 deadliest pests and diseases over the decade

One early morning in late December 2013, Mr Elijah Gitare left his house in Kirinyaga County to go to his tomato farm. He was full of expectations as he hoped to make a neat income from a bumper harvest. After all, the price of a 60kg crate of tomatoes was at a high of Ksh4,000.

He had been growing tomatoes commercially for over 10 years and had been earning some good money that helped to meet his and his family’s needs.

However, upon entering the farm that morning, was his worst nightmare. Instead of a healthy and robust crop, there were burnt stems and leaves, while the tomato fruits that had only earlier been fresh and nice to look at had ugly holes burrowed into them.

Within a few days, despite spraying the plants, the whole crop was infested and instead of harvesting the 30 crates he had expected, he only got two crates.

Mr Gitare had become one of the first victims of a vicious leaf miner codenamed Tuta Absoluta and nicked named Tomato Alshabab, a devastating crop pest that had just landed in Kenya, on the latest leg of its journey of destruction across the globe.

The pest, which crossed from Ethiopia into Kenya, reaching Isiolo, had travelled all the way from South America where it originates to Europe, Asia, and Africa.

On its arrival, it sent chills down the spines of farmers and sector stakeholders, quickly spreading across the country causing losses in its wake. Measuring only 7mm, the pest has a short lifespan and high reproductive potential, making it difficult to contain.

It has a strong preference for tomatoes on which it feeds aggressively but can also attack eggplants, sweet peppers as well as potatoes and various other cultivated plants. It is also difficult to control and easily becomes resistant to conventional chemical pesticides.

According to the Kenya Plant Health Inspectorate Service (KEPHIS), the pest can cause crop loss or damage of up to 100 per cent if not controlled.
However, Tuta Absoluta is only one of the emergent pests that have left the sector shuddering.

For over a decade now, the Kenyan plant and livestock health scene has gone through a plethora of invasive pests and diseases that has had farmers reeling in losses and organisations, including the government, scrambling to contain the situation.

These pests and diseases have led to significant losses, reduced yields, and increased costs of production, among other challenges that have impacted the agriculture sector.
In the crop sector especially, the sequence in occurrence has left farmers agape in dismay.

One after the other, like pestilence poured over the land, the diseases have invaded; if it was not the fruit fly invasion that came ravaging mangoes and avocadoes, leaving destruction in its wake and leading to export bans of the lucrative fruits, it was the fall army worm that invaded and wasted maize fields; while locusts in their millions swooped down and turned green, lash fields of vegetation into brown nothingness.

This situation has over the years put actors in the pest and diseases control industry into an overdrive to tame or control the invaders to stem the tide of losses and negative impacts on the economy.

While some of the efforts have been successful, the impacts of these pests and diseases continue to be felt across the country, and demand for action continues unabated.

Fall Armyworm

Coming hot on the heels of the notorious Tuta Absoluta was the Fall Armyworm (FAW), which checked into the country in 2016.

This pest attacks various crops, including maize, sorghum, and millet, and can cause up to 100 per cent crop loss if not controlled. It also originates in the Americas and was first reported in Africa in Nigeria. It then appeared across West and Central Africa.

FAW can lay up to 1,000 eggs during its lifetime and produce multiple generations quickly. The larva is spread mainly through wind dispersal on host plants from the eggs laid.
The Kenyan government, in partnership with various organizations such as FAO, CABI, and KALRO, has implemented various management interventions to control the spread of the fall armyworm.

These interventions include the use of biological control agents, such as parasitoids and predators, and cultural practices such as crop rotation.

Step-in the Desert Locusts

It is 2019. Step in, the desert locusts! Said to be possibly the worst invasion of desert locusts in 70 years, farmers and communities watched in horror as huge swathes of flying disasters landed on their fields and crops and within minutes left a bare landscape of brown expanse.

Many paid special attention to their TV sets, radios, WhatsApp chats …anxiously waiting to learn where the next attack might land.

Desert locusts are known to be highly destructive pests that can cause significant damage to crops, leading to food insecurity, economic losses, and environmental degradation. The locusts feed on a wide range of crops, including maize, sorghum, millet, and vegetables, among others.

The invasion, which run through to 2020, affected several countries in the region, including Kenya and led to loss and destruction.

The situation was worsened by the weather patterns, including the heavy rains experienced in late 2019 and early 2020. The rains created favourable breeding conditions for the locusts, leading to an exponential increase in their population.

But despite the gloom and doom, many came up with creative ways of controlling them. In some areas, women would gather, sing, clap, and make loud noises using drums and other instruments to scare the locusts away.

This would help as the pests would be disoriented by the loud noise and fly away. Others would use natural repellents, such as chili pepper and neem oil, to keep the pests away from their crops. Yet others still, resorted to eating or trapping them as feed for their chickens as a way of controlling their population.

In response to the locust invasion, the Kenyan government, in collaboration with several partners, launched a massive control campaign. The control campaign involved aerial and ground spraying of pesticides to kill the locusts and their eggs. The government also worked with the affected communities to sensitise them on how to identify and control measures.

Several organisations, including the Food and Agriculture Organization (FAO) of the United Nations, played a crucial role in supporting the locust control campaign in Kenya and the region.
FAO provided technical assistance, equipment, and training and developed an app that allowed farmers and locals to report sightings and swarm movements to the authorities for action.

The app was useful in monitoring and tracking the pests’ movements, enabling government to plan and deploy control measures effectively.

False codling moth

It was from a telephone call from KEPHIS one afternoon that Mr Daniel Agawo, the general manager of Jim’s Fresh Vegetables in 2016 learnt that his firm’s produce had been rejected. All the chili pepper they had harvested and sent to the buyer was to be discarded and they were staring huge losses in the face. Nothing would be salvaged from the farm from which the company had expected to harvest between 40 and 50 tonnes of bullet chilli and earn Ksh100 at farm gate price for every kilo. It was going to be a massive blow.

He learnt that the crop had been rejected because it had been attacked by the False Codling Moth (FCM) and did not, therefore, meet EU standards.

FCM is considered a major threat to Kenya’s horticultural industry affecting various crops including chili, citrus, avocado, and capsicum.

There have been fears that this moth could drive an entire value chain to its deathbed. This nocturnal pest damages crops by tunneling into fruit, feeding on the pulp causing rot and spoilage and fruit drop.

“It bites the fruit when it is still young, making it difficult to detect during the early stages,” said Mr Eric Ogumo, the chairman, Society of Crop Agribusiness Advisers of Kenya (SOCCA) at the time of our interview with Mr Agawa in 2016.

The biggest challenge from the FCM is visual observation to estimate the loss. To manage and control this pest, various interventions have been implemented, including the use of pheromone traps and the application of insecticides.

Maize Lethal Necrosis Disease

Another pest that has impacted Kenya’s agricultural sector is Maize Lethal Necrosis Disease (MLN). This disease, which is caused by a combination of maize chlorotic mottle virus and sugarcane mosaic virus, attacks maize crops and can cause up to 100 per cent crop loss if not controlled. MLN was first reported in Kenya in 2011 and has since spread to other countries in East Africa.

To manage and control MLN, various interventions have been implemented, including the use of resistant maize varieties and the distribution of disease-free planting materials. However, the lack of access to disease-free planting materials and the high cost of resistant maize varieties have hindered efforts to control MLN effectively.

The Fruit Fly menace

Despite their miniscule size, fruit flies are a menace to fruit and vegetable farmers, wreaking havoc on fruits, especially mangoes, oranges, avocados, and bananas.

The female fruit fly lays eggs under the skin of fruits and vegetables, which hatch into larvae that feed on the decaying flesh of the crop. Infested fruits and vegetables quickly rot and drop to the ground. Besides the direct damage, indirect losses are associated with importing countries preventing entry and the establishment of unwanted fruit fly species.

The fruit fly has cost the country millions in exports, with a total ban on Kenyan exports to some countries. In 2014, EU banned imports of Kenyan mangoes due to concerns over fruit fly infestations. The ban was lifted in 2016 after the country implemented measures to control fruit fly populations and improve the quality of exported mangoes.

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Photo credits :Wikipedia