The widespread use of pesticides contributed to the slowdown of the grasshopper invasion, but the consequences of the methodology had not yet been measured and evaluated.
A colony of giant grasshoppers is a terrible disaster. They begin with a black streak on the horizon, followed by darkening gradually. The small rustling noises gradually turned into the shrill noise of the millions of yellow insects that came. Since the end of 2019, grasshopper clouds have spread across the Horn of Africa, devastating crops and meadows, prompting people to trigger a massive campaign to destroy them. The ground and air spraying of insecticides in eight East African countries, coordinated by the World Food and Agriculture Organization (FAO), prevented the worst scenario – the destruction of the grasshoppers. the food source of millions of people. In 2020, according to FAO calculations, the campaign will preserve the amount of grassland and food enough for 28 million people in the Horn of Africa and Yemen in a year. But this progress has come with unspecified consequences for the environment, and the difficult problem is to find a way to destroy this invasive insect without destroying plants, harming insects, and wild animals. wild and human. The consequences have not been determined To date, 2.3 million liters of chemical pesticides have been sprayed on 1.9 million hectares, at a cost of about $ 195 million (according to FAO statistics). This campaign will continue this year. Assessment of damage to the environment is not complete, but the effects of the insecticide have been recorded for centuries in other areas. Extensive pesticides not only kill grasshoppers, but also bees and other insects. They penetrate into water sources and can affect human health. Dino Martins, executive director of the Mpala Research Center in Kenya, said: “Of course there will be uncontrolled damage. All these chemicals are made to kill insects, and they do it with that. bulk”. Grasshoppers formed in 2018, after a hurricane brought heavy rains to the Arabian desert, allowing them to breed on wet sand. Strong winds in 2019 push the flock to Yemen, then across the Red Sea into Somalia, Ethiopia and Kenya. Grasshoppers proliferate quickly and eat everything in the way they fly. Photo: National Geographic. The spraying was carried out even when the Covid-19 pandemic spread around the world. Wearing masks, hundreds of local volunteers and Kenyan conscripts wore aerosols and sprayed the grasshoppers with any pesticide in stock. They sprayed tens of thousands of liters of deltamethrin, as well as hundreds of liters of fipronil, chlorpyrifos, and other insecticides. In particular, many types are banned in Europe and some parts of America. In the reported case in the northern Samburu region, a ground control team sprayed 35 times the recommended amount of chemicals on an area, killing both bees and beetles. “Originally, this was an emergency situation. The idea was to try to control as quickly as possible to control the environment,” said Thecla Mutia, head of the environmental impact monitoring group of locust control efforts in Kenya. ensure food security “. Struggled to find an alternative Pesticides are poisons. Four types used in Kenya under FAO censorship have a high risk of harming bees, low to moderate to birds, medium to high with grasshoppers and soil insects, such as ants and termites. The European Union has banned the use of chlorpyrifos since early 2020, and some American states such as New York, California, and Hawaii also banned it. Fenitrothion is not approved for use in Europe, but is used in the US and Australia against grasshoppers. “We are not hiding the nature of the insecticide, but we cannot do anything while the grasshoppers spread. We want to reduce the number of desert locusts,” said Cyril Ferrand, FAO’s team leader in Nairobi. in a responsible way. Grasshoppers wreak havoc on crops with terrifying speed and scale. Photo: BBC. Biological solutions that are non-toxic, which can kill grasshoppers without harming other species, have been around for decades. However, chemical pesticides remain the top choice, accounting for up to 90% of the solution sprayed during the campaign in East Africa. The development of biological insecticides began in the late 1980s, after the grasshopper epidemic lasted for many years, stretching from North Africa to India. Christiaan Kooyman, a Dutch scientist who makes a bio-insecticide from the fungus Metarhizium acridum, which attacks grasshoppers, said: “When we see the number of millions of liters of pesticides sprayed, even the community. Donating them was also frightened. And they asked, ‘What else can I do?’ Metarhizium, marketed since 1998, has been proposed by FAO as “the most suitable control solution” for grasshoppers, but is rarely used. The drug works slowly, giving it a low “suppression” rate – that is, killing after days instead of hours. At the same time, its use was very expensive and difficult, more effective with young than adult swarms of grasshoppers – which was a great threat at the time. The biggest advantage of Metarhizium – just killing grasshoppers – also makes it a less profitable product. Companies make very little money making the drug, and go through the costly licensing process in one country and take a long time until it is allowed to be used. “Grasshoppers don’t usually show up, and businesses aren’t interested in producing something that isn’t used,” said Graham Matthews, a scientist on the Pesticide Review Foundation founding council. The grasshoppers come, you don’t want to wait for new production, you want a solution. As a result, governments have used wide-ranging, readily available chemical pesticides. Pesticides are the solution of choice to control grasshoppers. Photo: FAO. What worries the farmers, herders, scientists and conservationists of Kenya with these chemicals is that there is so much unknown – if any – about the harm they cause. A US government assessment warns “the risk of a significant negative impact on the environment and human health”, and the World Bank considers that the risk to the environment is “enormous”. “The use of large amounts of pesticides will of course harm biodiversity, but the magnitude of the effects has not been determined,” said Sunday Ekesi, an entomologist who joined his own anti-desert locust force. Nairobi, said. A major concern in Kenya is the impact of pesticides on pollinators. Farmers believe that the disappearance of bees is a factor in the low production of honey and mango. However, the lack of surveillance information makes it difficult for scientists to know what is actually going on. FAO’s 2003 guidance on safety measures shows that aerial spraying has no less impact on human health than ground spray, but often presents “more environmental concern” because There is a risk of entering sensitive areas in the ecosystem. In general, Kenya’s current grasshopper eradication campaign has improved compared to the first few weeks. If done correctly, the environmental impact will be very low. However, not many official reports have been published on this matter. Aircraft sprayed insecticides in the area invaded by locusts. Photo: FAO. Raphael Wahome, an animal scientist at Nairobi University, said FAO needs to release reports soon, so that researchers can evaluate more comprehensively. “Our main concern is that it’s all focused on locust control without the parallel monitoring system for undesirable effects,” he said. occurred where the “pesticide was used”.
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