Concerns about the use of pesticides
While South African farmers now have the tools to locate the swarms, conservationists are concerned about how the insects are being destroyed in this country. Chemical pesticides, the ongoing mechanism for doing so, contrasts South Africa with the environmentally friendly pest control methods used in other African countries that now use biopesticides.
During the locust infestation earlier this year in the Eastern Cape, the national government provided AgriEC with two helicopters to treat the swarms with chemical pesticides, in particular Sumi-Alpha and Deltamethrin, and also provided 16 “blowers” (portable units that teams of workers carried on their backs to spray insects).
“We had two situations where people used smoke instead, but that didn’t really help much, so the main thing [used] was poison,” Pretorius said, noting that in some cases the fires and smoke help repel locust swarms, although the insects simply fly off to another area.
Spraying fruits or vegetables intended for human consumption with toxic pesticides is prohibited in South Africa, so farmers often use the helicopter rotor to eliminate flying swarms by pushing them into unplanted spaces, where insects can be pulverized and their carcasses left to decompose. open ground.
One of the hopes is that the EarthRanger technology will allow farmers to quickly track down the larvae and spray them when they’re “not so active”, Pretorius said, requiring fewer pesticides.
AgriEC estimates that a chemical pesticide, once sprayed, only contaminates the soil for two weeks. However, new research published in May 2022 advises against chemical pesticides in favor of non-toxic biopesticides, such as the mushroom Metarhizium laughed at, to kill grasshoppers.
Academics led by Samuel Kamga from the University of Yaoundé in Cameroon have found that once early warning software predicts a locust invasion, experts can then calculate an optimal time when temperature and humidity are just M.acridum the fungus will grow. Ideally, for prevention, a mushroom-based biopesticide should be sprayed in areas that are likely to be affected before a swarm arrives.
Claire Nasike, Greenpeace Africa Campaign Manager in Kenya, also supports the use of M.acridumbased on biopesticides to control swarms. She says that, based on their chemical properties, some pesticides currently in use last well over two weeks in the soil, lingering and harming the microorganisms that make soil fertile for crops.
She noted that toxic chemical pesticides can travel long distances via surface runoff and then contaminate the water sources they flow into. “Some can seep into groundwater sources, eventually contaminating them and reducing the fresh water available for their use. Some, like deltamethrin, which is frequently used, have the ability to harm bees (which are essential food production) and fish.
M.acridum, on the other hand, only kills locusts and does not contaminate the environment. “It can be used to kill locust swarms,” says Nasike. “This method has proven itself in countries like Tanzania and Madagascar, provided it is applied in time. Toxic [chemical] pesticide use should not be a knee-jerk reaction to locust problems that can be solved with biopesticides and good planning.
In South Africa, farmers are eagerly awaiting September to see how well their early warning system for locust swarms is working and whether the insects can be effectively controlled.