Several countries in East Africa – namely Kenya, Ethiopia, Uganda, and South Sudan – are still trying to contain the worst desert locust invasion the region has experienced in over 70 years. The locusts have destroyed vegetation – especially staple cereal crops, legumes, and pastures – resulting in huge economic losses. The World Bank estimates that these losses could reach US$8.5 billion by the end of the year.
Unlike many other grasshoppers, the desert locust (Schistocerca gregaria) can change from a harmless solitary phase to a destructive gregarious phase whereby hoppers (juveniles in their early, wingless stages) march together in bands. The adults can fly and form giant swarms that can invade large areas away from their original breeding sites.
Currently, the countries are battling the second generation (or wave) of locusts, as they’ve already reproduced and hatched once within the region. And re-infestation could continue if the environment is conducive to it. Governments have tried to control these insects through a range of efforts: from mobilising military units to using young people as locust cadets.
An attemptpt to control and eliminate populations of flying locusts is expensive and not very effective. The best option, proved by scientists, is to manage them at their breeding sites. Eggs survive and hatch when the environmental conditions are right – they can hatch within weeks or remain undeveloped for years. They’re laid inside soil so can be hard to find; it’s best that control measures – preferably biopesticides – are used when the locusts are at the surface in the form of a nymph or hopper.
Personnel from International Centre for Insect Physiology and Ecology are trying to fill this gap. They have developed maps that predict where desert locusts could breed in Kenya, Uganda, and South Sudan. The model, supported by a machine learning algorithm, establishes a relationship between historical data from around the world on desert locust breeding sites. It also factors in climate and soil characteristics that are necessary for locusts to lay their eggs, and for the eggs to hatch. Breeding sites can consist of anywhere between 40 to 80 million locusts within a square kilometre.
Some of the intervention actions include; Due to a large area for potential breeding of locusts, a permanent locust monitoring unit in Kenya must be established. It should consist of ground and aerial surveillance teams, locust biologists, socio-economists, remote-sensing experts and weather and vegetation forecasters. Sustainable locust management interventions and associated mobilisation of financial, logistical and human resources need to be closely linked with strengthened locust monitoring efforts. Find out more about it here.