A massive invasion of desert locusts partly fueled by the climate crisis seriously threatens food security in already vulnerable communities across East Africa and has increasingly alarmed United Nations experts in recent weeks. The UN’s Food and Agriculture Organization (FAO) estimated one swarm in Kenya at around 2,400 km2 (an area almost the size of Moscow, Russia) meaning it could contain up to 200 billion locusts, each of which consume their own weight in food every day. If unchecked, locust numbers could grow 500 times by June, 2020, spreading to Uganda and South Sudan, becoming a plague that will devastate crops and pasture in a region which is already one of the poorest and most vulnerable in the world. The FAO says the current invasion is known as an “upsurge” when an entire region is affected. However, if it gets worse and cannot be contained, over a year or more, it would become what is known as a "plague" of locusts. There have been six major desert locust plagues in the 1900s, the last of which was in 1987-89. The last major upsurge was in 2003-05. A swarm contains up to 150 million locusts per km2 and can devour enough crops in a day to feed 35,000 people, according to FAO, a UN agency. The primary method of battling locust swarms is the aerial spraying of pesticides. FAO’s “Locust Watch” service explains that “although giant nets, flamethrowers, lasers, and huge vacuums have been proposed in the past, these are not in use for locust control. People and birds often eat locusts but usually not enough to significantly reduce population levels over large areas.”
A locust devouring vegetation in Morocco, July 2004 (Credit: FAO/Giampiero Diana/VOE)
FAO's Desert Locust Information Service (DLIS) produces maps indicating the perceived risk or threat that current desert locust infestations pose to agriculture.
Desert Locust risk maps–2020 (Credit: FAO's Desert Locust Information Service)
Key facts on locusts:
- Locusts are the oldest migratory pest in the world. They differ from ordinary grasshoppers in their ability to change behaviour (gregarize) and form swarms that can migrate over large distances.
- The most devastating of all locust species is the desert locust (Schistocerca gregaria). During plagues, it can easily affect 20 percent of the earth’s land, more than 65 of the world’s poorest countries, and potentially damage the livelihood of one tenth of the world’s population.
- During quiet periods, desert locusts live in the desert areas between West Africa and India–an area of about 16,000,000 km2 where they normally survive in about 30 countries.
- Three pests, the Italian locust, the Moroccan locust, and the Asian migratory locust, jeopardize food security and livelihood in Caucasus and Central Asia (CCA) as well as in adjacent areas of northern Afghanistan and southern Russian Federation.
- In CCA, 25,000,000 ha of cultivated areas are under threat and at least 20,000,000 people at risk, including the most vulnerable rural populations.
- Other locust species of economic importance in the world are: the red locust (Nomadacris septemfasciata) in Eastern Africa, the brown locust (Locustana pardalina) in southern Africa, migratory locusts (Locusta migratoria) throughout Africa and Asia, the tree locust (Anacridium melanorhodon) mainly in Africa, the Moroccan locust (Dociostaurus maroccanus) and the Italian locust (Calliptamus italicus) in North Africa, Europe and Central Asia, and the Australian Plague locust (Chortoicetes terminifera) in Australia.
- Locusts have a high capacity to multiply, form groups, migrate over relatively large distances (they can fly up to 150 km per day) and, if good rains fall and ecological conditions become favourable, rapidly reproduce and increase some 20-fold in three months.
- Locust adults can eat their own weight every day, i.e. about two grams of fresh vegetation per day. A swarm the size of Bamako, Niamey or Paris will consume the same amount of food in a single day as half the population of Mali, Niger and France respectively.
- If infestations are not detected and controlled, devastating plagues can develop that often take several years and hundreds of millions of dollars to bring under control with severe consequences on food security and livelihoods.