A historically rare locust plague is sweeping across East Africa and Eurasia.
Recently, East African countries, including Kenya, Somalia and Ethiopia, are suffering the worst desert locust plague in 25 years.
Desert locust plagues have ravaged East Africa on a large scale and have destroyed hundreds of thousands of acres of farmland. By the end of December last year, nearly 360 billion locusts had destroyed 175,000 acres of farmland in Somalia and Ethiopia, of which nearly 40 billion had reached China's bordering countries of India and Pakistan and were spreading to the northeast. Desert locusts reportedly invaded Pakistan's second-largest cotton base, Sindh province and the northeastern province of Punjab, where crops were largely out of harvest; locust plagues in India would reduce the country's food production by 30 to 50 percent.
On 11 February, the Food and Agriculture Organization of the United Nations (FAO) warned the world of a global high alert for the current ongoing locust plague and preventing a food crisis in invaded countries.
According to a report released by the Food and Agriculture Organization of the United Nations on February 17, more than 20 countries in West Africa, East Africa and South Asia have been affected by locust plagues, and Somalia, Pakistan and other countries have declared a state of emergency to deal with locust plagues. Locust plagues put crop production, food security and millions of lives at risk.
According to the latest news on February 18, the current locust plague in India has basically ended, and only a few locusts still gather in parts of the western state of Rajasthan. But the Indian government still issued warnings that a more severe locust plague could occur in June.
There are fears that if the locust plague spreads further, it is likely to approach the China, Japan and South Korea region. According to foreign media reports, two days ago, the locust swarm had reached the western border area of China, but the news has not been officially confirmed.
The "protagonist" of this disaster is the desert locust, which is a major agricultural pest in the river valleys and oases of tropical desert areas in Africa and Asia, with strong flight ability and large food intake, which can gather to form huge locust swarms.
It is estimated that this locust can move 150 kilometers a day with the wind, survive for about 3 months, and the main crops are wheat, corn, sorghum, rice, millet, sugarcane and so on. A single female locust can lay about 300 eggs, and a 1-square-kilometer swarm of locusts eats the equivalent of 35,000 people a day.
Where do desert locusts come from? Why is it suddenly raging in droves? How can locust plagues be contained? Will the locust plague invade China? Is my country adequately prepared to deal with the locust plague?
<h2>The devastating desert locust Desert Locust
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Locusts exist around our lives, people often say grasshoppers, grasshoppers, belong to a family of locusts, locusts can be called locusts. The locust family consists of 8 families, and what we usually call grasshoppers is mainly locusts in the family Locustidae and locusts in the genus Cone-headed locusts.
The locust outbreak is one of the short-horned locusts that inhabit the deserts of africa and western India, the Desert Locust.
The desert locust is considered one of the most destructive migratory pests in the world due to its ability to fly and eat a large amount of food.
Desert locusts
The desert locust has two short horns, has 1 pair of compound eyes and 3 single eyes, and has developed hind legs, with which it can jump tens of times longer than the body. Desert locusts are facultative diapause insects that overwinter in the soil with their eggs and feed on plant leaves when they reach adulthood. The locust prefers to eat reeds, barnyard grass, white grass, dogtooth grass and artemisia plants, shrimp whiskers and sea canopy, long-term nocturnal sunrise, no obvious phototropism.
These insects are usually solitary, becoming more abundant only in certain situations and changing their behavior and habits into social settlements.
When locusts grow in their infancy, they are harmless, their numbers are small, and they do not pose a major economic threat to agriculture. But when the vegetation grows rapidly under the right drought conditions, the serotonin in the locust's brain is rapidly stimulated, turning the solitary, harmless desert locust into a group of greedy, pervasive pests.
This triggered a series of dramatic changes: locusts began to multiply in large numbers, and when their populations became dense enough, they became gregarious and nomadic (described as migratory), forming colonies of winged adults and rapidly dispossessing fields, wreaking havoc on crops.
<h2>Why is there a locust plague? </h2>
As mentioned above, when adult locusts are crowded together (e.g., in areas where green vegetation is gradually decreasing), they cease to be solitary creatures and become "gregarious mini beasts", and locusts begin to flourish.
According to a 2004 paper in the journal Science, the locusts' transition from solitary to gregarious began when they attracted each other and gathered together, found and smelled each other's scents, or touched each other with their hind limbs. This touch forms a physiological stimulus in the body and stimulates serotonin chemicals in the nerves of the locust brain, which is a messenger that produces pleasant emotions. The paper's first author, Michael Anstey of the University of Oxford in the United Kingdom, points out that serotonin can play a "role in triggering a domino effect", which is an important chemical that causes changes in locust habits.
The current desert locust plague is closely related to the environmental changes in the region.
Desert locusts typically live in arid regions of about 30 countries between West Africa and India, an area of about 16 million square kilometers. Two years ago, hurricanes and heavy rains broke out in the southern part of the Arabian Peninsula, and the land became moist due to warming, which allowed desert locusts to thrive, according to the Food and Agriculture Organization (FAO).
A mixture of abnormal weather and climatic conditions fueled the locust plague.
According to National Geographic, a heavy rain in September 2019 encountered an extremely strong tropical Indian Ocean dipole orthode phase event, which led to an increase in precipitation along the East African coast, and September and October coincided with the time when the larvae broke through the ground, and the locusts naturally grew rapidly due to abundant moisture and good land environment.
According to the Food and Agriculture Organization (FAO), the locust swarms formed by the desert locust are dense and highly mobile, and they can fly 100 to 150 kilometers a day with the wind. According to statistics, the average adult locust can eat almost 2 grams of food a day, a female locust can produce about 200-400 eggs, from larva to adult only two or three weeks, there are more than 400 billion locusts, calculated, can eat more than 720,000 tons of crops and vegetation, and an adult can eat 400g of grain a day, a total of 35,000 rations a day.
In addition, the route of locust spread is also difficult to predict.
Keith Cressman, FAO's senior locust forecasting officer, said the swarms could not control their routes and were "victims of the wind". With drought and hot weather, desert locust swarms "follow the road" all the way to destroy crops.
Spreading from Yemen just before March, locusts have reached North Africa, flew over the Red Sea, into the Middle East and South Asia, and are now wreaking havoc in Pakistan and India.
Although there is a natural barrier between China and India and Pakistan in the Tianshan Mountains, Kunlun Mountains and Himalayas, the possibility of desert locust swarms migrating into China is low, but it is not excluded that locust swarms will migrate from western India to the east and enter Southeast Asian countries such as Myanmar and Laos.
Road map for locust plagues in Africa
In fact, at the end of 2018, there was already a round of locust plagues in Africa. Due to the low proportion of controlled locusts, the large number of residual locusts, coupled with the climatic conditions suitable for the occurrence of desert locusts this year, this year's desert locust disaster has intensified.
<h2>The Great Locust Plague of History</h2>
In fact, in the past two thousand years, locust plagues have never been eradicated and continue to appear at irregular intervals.
Due to its preference for arid and low vegetation, locust outbreaks are concentrated in Africa, the Middle East and Europe. In the 1970s, 1980s and the 21st century, desert locusts were rampant in eastern Africa, along the Red Sea coast, the Middle East, and West Asia and South Asia.
As early as 2470-2220 B.C., the ancient Egyptians carved locusts on their graves; the biblical Book of Exodus mentions that devastating plagues are associated with locusts; and locust plagues are also mentioned in the Qur'an. Usually after changing the direction of the wind or weather, these swarms of locusts multiply and spread, and the consequences are catastrophic.
Locusts in the painting
There is also no shortage of records of locust plagues in China's history books.
According to the article "Locust Plague in Ancient China", the earliest record of locust plague in ancient books is recorded in the Spring and Autumn Period in the fifteenth year of Lu Xuangong (594 BC): "The first tax acre, winter, and bat life." The Confucian classic "Li Ji Yue Ling" also has a record of "locust plague". Xu Guangqi's "Complete Book of Agricultural Politics and Eliminating Locusts" of the Ming Dynasty counted the number of locust plagues in the Spring and Autumn Period (770-476 BC), pointing out that there were 111 locust plagues in the Spring and Autumn Period in 294.
In 311 AD, a plague in China's northwestern provinces killed 98% of the local population. According to the epidemiological book Plagues and Peoples, researchers have found that the outbreak was related to locusts, possibly due to an increase in the number of rats (and their fleas) that devoured the carcasses of locusts, the earliest recorded locust death.
Looking closer, from 1998 to 2001, there were successive serious locust plagues in China's Huang-Huai-Hai region, and even in Huludao, Liaoning Province, there were also locust disasters, according to statistics from the Institute of Plant Protection of the Chinese Academy of Agricultural Sciences, in 2001, the area of East Asian locusts in China was about 1.916 million hectares (not including the area that occurred in Hainan Province).
<h2>Locust swarm disasters are not unrelated to human factors</h2>
Recent studies have shown that although locust plagues are an international natural biological disaster, they are not unrelated to human factors.
A scientific report written by Wang Zhengjun, Qin Qilian and others of the Institute of Zoology of the Chinese Academy of Sciences shows that the backwardness of human activities and monitoring and early warning techniques is the main reason for the spread of locust plagues.
In recent years, the change of the planting structure of land-use crops has artificially increased many conditions conducive to the occurrence of locusts (water, heat, food, etc.), the transformation of coastal, lakeside and river beaches has not received due attention, and the poor management of pastures in pastoral areas (such as blind reclamation, indiscriminate digging, and indiscriminate trees), etc., the degradation and desertification of grasslands caused by overloaded grazing have created favorable conditions for the reproduction of locusts and led to serious damage to pastures. These improper human activities are bound to cause a great locust plague and further cause the deterioration of the ecological conditions and environment in the locust area.
Once the locusts reproduce, they can form a large number of locust swarms, the area of occurrence is very wide, the ecological conditions are different, complex and diverse, the team of investigation and reporting personnel is unstable, the professional quality is not high, the monitoring and early warning technology is far behind, and under the linkage between the environmental protection cause and the political environment, the locust plague has not been effectively paid attention to and controlled in the early stage, until the locust plague spreads on a large scale, and then the epidemic is curbed.
Forecast information can not meet the needs of governance work, decision-making departments are difficult to grasp the locust outbreak time in a timely, accurate and comprehensive manner, these factors add up, directly lead to the locust swarm disaster has not been able to effectively control.
<h2>There is no targeted and effective method, and the chicken and duck flocks are basically useless</h2>
In fact, there is no very targeted and effective way to completely control the locust epidemic, and only some means are used to prevent the locusts from reproducing.
In the early 20th century, farmers were cultivating the soil of eggs, collecting locusts with flytraps and killing locusts with flamethrowers, destroying the growth of locusts. It has been documented that the use of organochlordrin as an insecticide is effective in killing locusts in some areas, but eventually because of its persistence in the environment and its bioaccumulation in the food chain, its use was later banned in most countries.
And there is also a tone on Weibo, saying that the desert locusts into China are fine, we have long had a trick: let chickens and ducks eat locusts, green environmental protection, chickens and ducks can sell money when fat.
However, according to the understanding of titanium media, this model mainly prevents and controls Siberian locusts, small-winged curved-backed locusts, chick locusts, euphorbia locusts, and pasture locusts, and this locust only appears in Xinjiang and Qinghai grasslands. Chickens and ducks have little effect on desert locusts, after all, the locusts have to migrate over long distances, and they cannot be successfully captured in terms of distance and number. Moreover, this method can deal with ordinary, early locust plagues, and it is a drop in the bucket to really put them in the environment of flying locusts.
In addition, the natural chain has a natural enemy effect, and the desert locust has many natural predators, such as predatory wasps and flies, parasitic wasps, predatory beetle larvae, birds and reptiles. If the locust killing measures were carried out by natural enemies, it is likely that isolated populations would be effectively controlled, but due to the current large number of locusts, this effect is in fact very limited.
The public should clearly understand that large-scale desert locusts are pests that are difficult to control. And because locust swarms reproduce mainly in remote rural areas, factors such as infrastructure and limited resources for locust monitoring and control may exacerbate locust outbreaks and further reduce the ability to monitor and control activities necessary for locusts.
Accordingly, effective containment of locust outbreaks depends on two main factors: monitoring and effective control.
Currently, the Food and Agriculture Organization (FAO) has developed a desert locust information service that provides forecasts, warnings and alerts for invasions, breeding times, scales and locations. Once the values reach critical levels, urgent action is needed to reduce locust populations and prevent more colonies from forming and spreading.
Another factor is effective control, as mentioned above, desert locusts are difficult to control, then, in order to contain the locust epidemic, the ultimate goal is the locust swarm to minimize the damage to the environment, and gradually with the weather factor, the locusts are effectively controlled. After all, this approach will make crop production easier and safer in many regions, and the growth of crops is crucial to the survival of the local people.
"In Kenya and Ethiopia, preferably in Somalia, large-scale air control operations are needed now, but this is not possible due to the security situation." "Since [locust] populations are now concentrated in flocks, it is ideal to hit them hard with an airplane so that the number of locusts that may mature and lay eggs can be reduced," Kressmann said.
Although more environmentally friendly solutions, such as biopesticides or the introduction of natural predators, are currently being studied, the most commonly used control method is pesticide spraying. By means of a hand pump, a land vehicle or an aircraft spraying it onto the pest, the entire swarm can be aimed at the target and killed with chemicals in a relatively short period of time.
An effective means of curbing locust outbreaks
Aerial spraying has intensified efforts to resist locust incursions, but controlling such a large number of locust populations in large remote areas remains an important challenge.
In addition, early warning and preventive control are strategies adopted by locust-affected countries in Africa and Asia aimed at halting the progress and spread of locust plagues. Between the 1920s and the 1930s, locust control became a major area of international cooperation. Locust plagues, droughts and floods, and called the three major natural disasters in history.
<h2>The risk of a large-scale outbreak of locust infestation in the country is low</h2>
From the domestic point of view, with the improvement of China's agricultural infrastructure, the scale and frequency of locust plagues have dropped sharply, and there has been almost no particularly large harm.
In response to the locust epidemic, the Ministry of Agriculture and Rural Affairs said that the risk of large-scale outbreak of locusts in China is very low.
Shi Wangpeng, director of the Department of Entomology of China Agricultural University, said in an interview with the media that the overall situation of locust infestation in China in the past 10 years and more has declined for many years, but there is still a risk of locust outbreak in some areas, coupled with the risk of invasion and harm of foreign locusts, so it is not to be taken lightly, and it is necessary to closely do a good job in monitoring and prevention work and wait in a strict line.
At present, aid organizations are doing their utmost to prevent the locust crisis from worsening. Last month, FAO called on the international community to allocate US$76 million for pest control activities to protect farmers and pastoralists in five locust-infested countries.
(This article was first published by Titanium Media, written by |.) Lin Zhijia, Editor | Zhao Yuhang)
References:
http://www.fao.org/locusts/zh/
https://www.bbc.co.uk/news/resources/idt-84994842-8967-4dfd-9490-10f805de9f68
https://www.nationalgeographic.com/science/2020/02/locust-plague-climate-science-east-africa/