“When there are too many of them, they are very destructive, but each other, what’s not to love?” Arian says. She is referring to locusts.
Siez leads Arizona State University’s Global Locust Initiative, where she studies how locusts behave and the way their destructive populations may be controlled. Although her research focuses on reducing damage to crops and communities, she also brings a deep respect for the insects themselves.
Locust swarms remain a world threat
For many individuals, locusts conjure up images of ancient plagues, but today’s threat could be very real. Worldwide, sheep can destroy crops over vast areas, wipe out livelihoods, and disrupt education and long-term economic prospects for youngsters in some areas. A swarm can cover a whole bunch of square miles—roughly the dimensions of a big city like New York City or Phoenix.
That’s why Says and his international research team paid close attention once they identified a simple, soil-based method to scale back grasshopper feeding. Scientists soon realized that this approach could have life-changing results. To their knowledge, that is the primary study to check the tactic in an actual farming environment and show that it really works outside the lab.
Testing the thought with farmers in Senegal
The researchers partnered with farmers in Senegal who usually experience outbreaks of Senegalese locusts. Unlike the desert locust, this species doesn’t form large populations, but its frequent occurrences and small groupings could cause even greater harm to local farmers. These communities had earlier cooperated with the ceasefire and pushed for a bigger field study.
Each farmer planted two plots of millet.
The opposite was clear. Fertilized plots had fewer locusts, less crop damage, and crops that were twice as large as untreated plots.
“These advances represent an important step in the sustainable management of migratory pests, offering a community-based tool that expands the available treatment options,” said Says, who can also be an associate professor within the ASU School of Sustainability and School of Life Sciences.
The research was published within the journal Gaston Berger, associate professor on the University of Saint-Louis in Senegal, served because the lead creator, while Cies was the principal investigator of the USAID-supported project.
“The findings are important to the scientific community and to Senegalese farmers as well,” Touré says.
Why soil quality shapes grasshopper behavior
The Global Locust Initiative is an element of the Julie Ann Wrigley Global Futures Laboratory and focuses on the various systems that influence locust outbreaks. Environmental conditions, insect biology and behavior, economic pressures, public policy, and land management all contribute to – and create opportunities to disrupt – cycles of destruction.
After greater than 15 years of research, a consistent pattern has emerged from stopping. Crops grown in nutrient-poor soils encourage the spread of locusts because these plants have high levels of carbohydrates and little or no protein.
“This carbohydrate bias, or ‘don’t food plan,’ is perfect for grasshopper populations and grasshopper populations. Like most endurance athletes who depend on carbohydrates for energy, grasshoppers rely upon carb-heavy plants to fuel their long-distance locomotion.
Plants growing in nitrogen-rich soils tell a distinct story. They are high in protein and low in carbohydrates, making them a difficult meal for grasshoppers. Their bodies struggle to process excess protein and fail to get enough energy to thrive.
Protein-rich plants deter pests
These results raised a crucial query. Can changing the balance of protein and carbohydrates in crops prevent locust damage? Earlier lab experiments and field observations indicated that it would, but the thought had never been tested on working farms. To stop, this gap made the following step clear.
Two Senegalese villages that had collaborated with him before volunteered to participate. Their farms usually suffer severe damage from Senegalese locust swarms.
In the experiment, 100 farmers each grew two millet plots – one treated with nitrogen fertilizer and one untreated for comparison.
The researchers weren’t sure whether locusts could still enter treated plots of nearby treated fields or whether the high-protein plants might attract other pests. To discover, the team counted locusts through the growing season and measured crop damage and recorded yields at harvest.
The results were decisive. Treated plots had fewer locusts, less leaf damage, and doubled millet yield at harvest. The team also found no evidence that adding nitrogen worsened other pest problems.
From compost to compost solution
Although nitrogen fertilization was provided for the study, it will not be a practical long-term option for a lot of farming communities. Sustainable control requires cost-effective methods that also protect soil health.
“Ongoing work is specifically focused on composting, and we seem to be getting the same results,” Says says.
USAID funding for the project led to early 2025, but farmers in Senegal have continued the composting approach themselves, encouraged by the outcomes.
“The farmers have unanimously said that they do not burn crop residues after clearing the land, but instead practice composting to fertilize their fields, thus helping to reduce the diseases of the grasshopper. Thanks to this project, this technique was fully mastered,” says Touré.
The research team is now looking for additional funding to expand the work to other regions heavily infested with locusts.
Why grasshopper research is very important to the United States
The United States currently has no native grasshopper species. So why study them? Jung says that might change. She is closely monitoring the Central American locust, whose range reaches as much as 200 miles from the US border.
“We can say with a lot of certainty that Texas will be very suitable for locusts in about 10 to 15 years,” says Sezius. “Whether or not they will cause a problem remains to be determined, but it’s something we should definitely be aware of.”
Even without locusts, locusts already pose major challenges across the country. There are 12 key species known collectively because the Dirty Dozen.
According to the U.S. Department of Agriculture, these 12 rangeland grasshoppers (plus one cricket) are amongst probably the most serious pest threats within the western United States. When they develop into overcrowded, they’ll eliminate grazing land and livestock for food, causing serious problems for farms.
Although chemical insecticides remain the first control tool, the Global Locust Initiative is working to discover alternatives which might be safer for people and the environment.
What scientists learn from locust outbreaks abroad could prove critical at home, helping the U.S. manage migratory pests more effectively and prepare for the likelihood that locusts may someday cross the border.