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A veritable Desert Locust epidemic devastates East Africa for the second year in a row. The flying insect reproduces exponentially, and tens of millions of locusts devour fields cultivated for human food. </p><div> <p><span><span><span><span><span><span><span>You could hear the rain falling. It is in reality a cloud of locusts which fell on a field of culture, and which devours everything in its path. A desert locust swarm numbers several million and last year, at the height of the crisis in East Africa, a flying swarm as large as Luxembourg was observed.</span></span></span></span></span></span></span>
The first signs of this aerial and cyclical terror in the region date back to 2018, after the passage of two cyclones, which caused a rise in humidity on the Arabian Peninsula, favorable to the development of Schistocerca gregaria, also called “the tiger grasshopper” … In a few months, the locusts will reach East Africa as far as Kenya. When they are born, the larvae are wingless, and are content to progress on the ground. In the desert, locusts are solitary. But the catastrophe is announced when they adopt a herd behavior and form nomadic swarms of millions of individuals, able to move several tens of kilometers in a day to find their food.
Ravenous locusts when they are in the billions
« They are ravenous! They eat roughly the equivalent of their weight each day, explains Cyril Piou, researcher at CIRAD, the Center for International Cooperation in Agricultural Research for Development, involved in Montpellier in the fight against the ravages of the desert locust on agriculture. Two grams is not much when there are ten of them, but when there are billions of them, millions of tons can be consumed. »
A single swarm of 1 square kilometer can swallow up the equivalent of the consumption of 50,000 human beings in one day. Behavior “Catastrophic” for agriculture, “When they arrive on fields where the plants are just beginning to grow. The vegetation is then completely razed and the crop will be lost for the current season. », Continues Cyril Piou. Since 2020, food crisis alerts have multiplied from the Horn of Africa to Kenya.
No predator can overcome it
For the desert locust, one of the great migrators of the animal kingdom, unity is strength and protects predators unable to regulate an exponentially growing population when the conditions are right. “No predator can go as fast as him, notes Cyril Piou. Desert locust population dynamics are explosive. Each generation multiplies by 3 or 4 the numbers, and up to 20 times in a very good situation. »Knowing that a female lays a hundred eggs, she generates (in theory; all larvae do not survive) offspring of 400 individuals. An exponential Desert Locust outbreak – doesn’t it ring a bell? We are now in the eighth generation since the invasion of the Horn of Africa. And the Desert Locust is always one step ahead.
On February 6, 2021, the Secretary General of the United Nations launched yet another call for international mobilization. “ I call on the international community to respond swiftly and generously to ensure an effective response and control the invasion while we still have the chance. António Guterres said at the African Union podium in Addis Ababa, Ethiopia, one of three endangered countries along with Somalia and Kenya, as locusts approach Uganda and from South Sudan.
A chemical cloud against the locust cloud
The UN needs money to finance the fight against “the tiger grasshopper”. A chemical fight, in an emergency. Apart from a biopesticide based on a fungus, most of the means used are based on the massive use of industrial products. “ We give planes or helicopters the coordinates of a swarm that is landed in the evening, says Cyril Piou. In the morning, early enough, before the swarm takes off again, we will carry out a broad spectrum chemical spraying which will kill many species other than desert locusts, birds and other cold-blooded animals. It is therefore a huge environmental problem, since the quantity of pesticides released is enormous. »
It is a long struggle. “ It’s not a dynamic that can be broken in a few days », Notes the desert locust specialist. The fight against locusts relies on the responsiveness of a network of observers being developed in East Africa. A mobile application has been set up to report the progress of the swarms in real time. West African countries already have a network in place, with the support of CIRAD, after the last food crisis caused by the invasion of desert locusts between 2003 and 2005. There has not been one since. . Because it is better to prevent than to face a wall.
It is so small that it is difficult to see it… And the plant that produces it itself measures only 2 millimeters at most. Wolffia is the name of this genus also called duckweed. On the surface of the water, rootless, small, but strong. She is also the fastest growing in the world and gives birth to a new plant every 36 hours. An invasive, edible plant that contains almost as much protein as soybeans. According to researchers, famine could be beaten with a dish of duckweed.
Source site www.rfi.fr