When Pharaoh failed to keep his promise to free the Israelites, Moses summoned a swarm of locusts to devour all vegetation in Egypt. In the Old Testament book of Exodus, it is the eighth of the 10 plagues that struck Egypt.
The terror of locust swarms remains the same today. In spring 2020, locust swarms that swept through 10 East African countries consumed 160,000 tons of food in a single day. That is enough to feed 800,000 people for a year. The World Bank estimated crop damage that year at $850 million (12.495 trillion won).
Scientists have found ways to quell the fear of locust swarms. U.S. and Senegalese scientists developed an easy method to make crops unappealing to locusts. Chinese scientists proposed controlling hormones so solitary locusts do not form swarms. It is a team of scientist Avengers facing down the locust swarms.
◇Lower carbohydrates so they do not suit locust tastes
An international research team led by Arianne Cease of Arizona State University said on the 15th (local time) in the journal Scientific Reports that it "developed a simple soil improvement method to prevent locusts from eating crops and confirmed its effectiveness together with African farmers."
The team tested a new control method in cooperation with Senegalese farmers affected by locust swarms. The Senegalese locust (Oedaleus senegalensis) is less destructive than the desert locust (Schistocerca gregaria) that swept East Africa but consistently forms small swarms that inflict major damage on farmers.
Simply put, the new method is to make the soil more fertile. Cease said, "Through more than 15 years of research, we found that plants grown in nutrient-poor soil promote locust swarming." In the experiment, 100 Senegalese farmers tended two plots of millet. One received nitrogen fertilizer, and the other was left unfertilized as before.
After three trials, the fertilized plots had fewer locusts than before. With less natural leaf damage, yields doubled. Farmers worried that nitrogen fertilizer might attract other pests, but no such problems arose. Locusts also did not concentrate more heavily in the unfertilized plots.
Protein was the key to driving locusts away. Millet grown in fertilized plots had higher protein and lower carbohydrates than elsewhere. Locusts avoid such plants. Just as marathoners load up on carbohydrates before a race, locusts concentrate on carbohydrates to get the energy needed for long-distance travel.
The problem is money. Cease said, "To achieve long-term effects, we need a low-cost way to supply nitrogen to the soil." This experiment was possible because the U.S. Agency for International Development (USAID) provided nitrogen fertilizer. But U.S. funding was halted last year.
Senegalese farmers have found a way to source fertilizer themselves. Mamour Touré of Gaston Berger University of Senegal, a co-corresponding author of the paper, said, "Farmers are no longer burning leftover stalks and leaves after harvest; they are composting them and using them for the next season." It is akin to Korea's Saemaul Undong, which was driven by a spirit of self-help that avoided reliance on others.
◇Technology to block the hormonal signals that summon swarms
Locust swarms threaten human survival. Desert locusts can mass at roughly 80 million per square kilometer. A desert locust swarm of that size consumes in a day the crops that would feed 35,000 people. The Food and Agriculture Organization (FAO) warned during the East Africa outbreak in 2020 that it could trigger a food crisis for one-tenth of the world's population.
Desert locusts are originally solitary, but when they form groups for certain reasons, they suddenly exhibit aggressive behavior. They devour all plants and animals they encounter while moving. Scientists are seeking the causes of swarming to find ways to reduce the damage.
A team led by Le Kang of the Institute of Zoology, Chinese Academy of Sciences reported in 2020 in the journal Nature that it identified a pheromone secreted when desert locusts swarm. Pheromones are signaling substances insects secrete outside the body.
The team collected six pheromones secreted by gregarious locusts and tested them. They found that a pheromone called 4-vinylanisole (4VA) leads solitary locusts into swarms. 4VA attracted not only solitary locusts but also those already in groups. This held regardless of sex or age.
Kang said, "When three or four gather, they start releasing 4VA, and as the group grows, the concentration of 4VA surges." It is like evolving from calling colleagues together with a loud voice to sending a rallying signal nationwide over broadcast. The team coated sticky traps with 4VA and set them in breeding sites in northern China. Traps coated with 4VA caught more locusts than other traps.
◇Curbing climate change is the fundamental solution
The Chinese team also proposed a way to prevent locusts from detecting pheromones at all. They knocked out the gene so the protein that detects 4VA would not form in the desert locust's antennae. The locusts then showed little response to 4VA. Kang's team reported in Nature last year that it blocked two key enzymes for 4VA synthesis and prevented gregarious behavior.
Some argue that averting a global food crisis requires looking beyond locusts themselves. Researchers at the Climate Prediction and Applications Centre (ICPAC) under the Intergovernmental Authority on Development (IGAD) in Africa reported in 2020 in Nature Climate Change that desert lakes formed by rains across the Arabian Peninsula created ideal conditions for locust proliferation.
According to the researchers, in May 2018 a tropical cyclone formed in the Indian Ocean and moved up to the Arabian Peninsula. The resulting downpours created desert lakes. In October of the same year, another cyclone moved into the region and added more moisture. By late 2019, cyclones generated strong winds that blew desert locust swarms into East Africa.
Ninety percent of the heat from human-caused warming is absorbed by the oceans. As a result, sea temperatures have risen and cyclones have become more frequent than before. In short, climate change summoned the desert locust swarms. As with Egypt's Pharaoh in the past, the cause of the locust plague lay with humans.
References
Scientific Reports (2026), DOI: https://doi.org/10.1038/s41598-025-27884-z
Nature (2025), DOI: https://doi.org/10.1038/s41586-025-09110-y
Nature (2020), DOI: https://doi.org/10.1038/s41586-020-2610-4
Nature Climate Change (2020), DOI: https://doi.org/10.1038/s41558-020-0835-8