In recent times, desert locusts have been raging around the world, causing panic among the people. The people of East Africa have long been engaged in intense hand-to-hand combat with locusts, the Ugandan government announced that it would send more than 2,000 military personnel to deal with the locust plague, and the Pakistani air force sent 149 fighter planes to fight the locusts.
Just as the so-called thinking of danger in times of peace, the broad masses of the people in our country have long thought of a way to control the locust plague, that is, to produce chickens out of all hands. No, the CCTV documentary "Herding Chickens to Control Locusts" was once praised by netizens on the hot search, saying that this is a method of controlling locusts with Chinese characteristics. But does this approach really work? In addition, what other ingenious methods of locust control does China have?
Without this locust warning, I am afraid that few people know that chickens and ducks still have that much effect. In 2001, when there was a locust plague in the grasslands of Hebei Province, the locusts were wiped out by a group of herders. And this herding chicken only trained to about 90 days before going to the battlefield, they transformed into "mobile locust chickens", within 5 days to solve the locust plague of nearly 1,000 acres. When the locusts are finished, the chickens are just fattened and can sell for money, which is really killing two birds with one stone.
However, what everyone ignores is that the control of locusts by herding chickens is only applicable to the locust disasters that occur on the grasslands of our country. If you encounter a relatively high pasture, you need ducks to appear. Whenever the duck's paw is stepped on, the locust jumps up, and the duck sticks out its long neck to swallow the locust into its stomach, imagining the picture is very beautiful.
However, according to scientists, these chickens and ducks prefer to eat scattered locusts, and once they become social, they will not eat. Therefore, chickens and ducks may be able to deal with the soil locusts on the grasslands of our country, but in the face of the desert locusts that may have recently invaded, they may not be of much use.
The locusts are rich in nutritional value, can we people eat them directly? In fact, since ancient times, some people have eaten locusts to control locust plagues. Legend has it that the earliest person to eat locusts was Li Shimin of Tang Taizong. At that time, the locust plague was serious, but Li Shimin sympathized with the people's feelings but felt helpless, so he ignored the persuasion of the courtiers and grabbed the locusts during the inspection and swallowed them raw. Such a move not only won the hearts of the people, but also caused the people at that time to rise up the eating habit of eating locusts.
But because the locusts have nibbled up the crops and flew away immediately, they will not wait for you to eat it. Therefore, the hungry people still had food on the two days of the locust plague, but after the locusts flew away, the hungry people had no food and famine, so they could only gnaw on the bark. Therefore, whether it is a person or an animal, it is difficult to solve the problem of locust plague by eating. In other words, China's achievements in controlling the locust plague are not at all earned by chickens and ducks and foodies!
Since we can't eat it, how do we deal with the locust plague? In the past, people's way to control locust plagues was relatively simple, that is, to plough the river beaches and saline land where locusts spawned, and then set them on fire. It was soon discovered that digging eggs could only reduce the number of locusts, not the area of locusts, and repeated ploughing would destroy the soil environment. Therefore, we have basically no effective measures to control locusts, and we are always bullied by locusts. It wasn't until the late 1960s, when we started using chemical pesticides, that we finally ended the history of frequent locust plagues.
However, since the 1980s, the global climate change has been abnormal for many years, resulting in river outages, frequent dehydration of reservoirs, and an increase in the frequency of locust occurrence, which has aggravated the degree of harm. The abuse of chemical pesticides has also caused the ecology to be damaged to varying degrees. As a result, more and more biotechnologies are being developed and applied to locust control.
In nature, there is a class of microorganisms that can infect insects and make them sick. To insects, these microbes are simply demonic beings. The pathogenic microorganisms of locusts mainly include microspores, fungi, bacteria, viruses and other species.
Among them, the locust microspore (Nosema (Paranosema) locustae) is a single-celled eukaryotic pathogenic microorganism that can infect more than 100 species of orthoptera insects. Its greatest feature is its ability to spread to the next generation through the eggs of diseased female locusts.
These microspores first sneak into the locust's favorite food, and when the gluttonous locusts come, they enter the locust's digestive tract with the food. Immediately after that, the spores set up camp there, protruding violently from the tip of the polar filament, penetrating into the host cells and the cells of the intestinal wall of the midgut, reaching the blood cavities, and entering the receptor histiocytes. For example, in the fat body, asexual fission reproduction begins, the spore plasmode of the spores is released, and it begins to multiply in large quantities in the cells of the host.
A, spores; B, spore wall; C, polar filaments
Because microspores consume energy substances in the locust's body, after the locusts are infected with microspores, their physical strength will slowly decline, and finally they will be weak and die. In addition, the number of eggs laid by locusts infected with microspores has decreased by about 50%, the hatching rate is extremely low, and the severe loss of fertility is direct.
In addition to cutting off locusts, locust microspores also inhibit locust swarm behavior. We know that they are also locusts, and when they are scattered, they do not cause much harm. And when they gather together and move, they will do harm everywhere, and there will be no pieces of armor left everywhere they go.
For the East Asian flying locust, the social body color will become black and yellow, better at flying long distances, and will move in the same direction as the same kind, and finally form a large army. The social type of desert locust is that the juveniles are darker and the adults are more bright yellow.
Solitary and gregarious forms of desert locusts
Studies have found that locust microspores can significantly inhibit the swarm flight of locusts. It mainly inhibits the purpose of inhibiting locust clusters by interfering with the synthesis of genes such as serotonin and dopamine, which regulate the cluster of locusts and the mutations;
Compared with chemical pesticides, locust microspores not only do not pollute the environment, but also are harmless to humans and animals. Therefore, locust microspores are being used by people to control locusts. So far, locust microspores have been promoted in major locust areas in the world, showing a good locust control effect.
In addition to microspores, insect pathogenic fungi are the largest taxa among insect pathogens. According to a field survey of wintering insects, about 60% of insect diseases are caused by fungi. As a result, pathogenic fungi have long been used to control pests like locusts.
Among them, the number one killer in the insect world, the green zombie fungus, also likes to poison locusts. Not only that, but the green zombie bacteria can also form inter-locust infections, resulting in "super epidemics" that spread within the population. It is no exaggeration to say that it is the locust buster that evolved from nature.
Green Zombie
The first scientist to discover the green zombie was the Ukrainian microbiologist Mechnikov. At that time, he observed that a group of dead scarab beetles would produce hyphae from insects two days after they died. The hyphae are white at first, then turn green, and finally dark green. Later, such pathogenic fungi were also known as green zombies. Its greatest strength is its "virulence" through the iron walls of copper.
When the green zombie comes into contact with the locust, its fungal structure can penetrate the wall of the locust and smoothly enter the locust body. The green zombie bacteria then dominate, using locust nutrients to multiply and secrete toxins, so that the locusts die of illness within 5 to 12 days and become a green corpse.
But that's just the beginning. Dead locusts can turn into "production workshops" for green zombies, becoming super-infected sources that continue to infect other locusts. It is precisely because the green zombie bacteria can grow from the insect body and spread, and its effectiveness is longer than that of chemical pesticides, and it has a continuous control effect on the pest population at a single application.
Locusts infected with green zombies
However, after years of follow-up investigations, scientists have found that the natural prevalence rate of fungal diseases in locust swarms is very low, and the rate of natural susceptibility in Locust swarms in African savannahs is about 2% to 6%. Therefore, in order to control locusts below the level of economic harm, it is necessary to artificially multiply and apply them to locust swarms, increase the susceptibility rate of locusts and reduce their population density.
However, it is not easy to screen out the right green zombie bacteria. First of all, scientists must ensure the number and diversity of collected strains from the sample, and then the targeted isolation of green zombie bacteria, the establishment of a screening process in the laboratory, the screening of highly virulent strains, field experiment verification, and safety evaluation, each step is very important and indispensable. Fortunately, the locust-killing green zombie fungus has been tested in a large area of Africa and used for the control of desert locusts, which can play a certain role in the locust plague caused by the desert locust.
In recent years, scientists have made great strides in fungal control of locust plagues. Significant progress has been made in strain selection, production technology, dosage form and control objects, and the development of locust-killing green zombie biopesticides in many countries has achieved important results, and the products have been demonstrated and tested in many regions at home and abroad. Not only that, scientists have also tried to add collateral substances such as neem seed oil to fungal pesticides to develop new dosage forms to improve the locust killing toxicity of pathogenic fungal pesticides.
With the help of nature's forces, scientists are also beginning to look for related viruses to solve the locust plague. The virus mentioned here refers to all viruses that can be hosted by locusts, and although some viruses can proliferate in locusts, they generally do not show pathogenicity to locusts.
In a narrow sense, a locust virus is a virus that hosts locusts and is pathogenic to locusts. After the locust virus infects the host by mouth, it can achieve effective infection between individuals, and the host of the locust virus is relatively specific, the safety is high, and it is safe and harmless to people, livestock, poultry and crops. Currently, viruses isolated from locusts include poxvirus and crystalline array virus populations.
The earliest report of the Xinjiang Siberian locust pox virus in China in 1981 by Huang Chuanxian is a B virus without spindles. Locust pox virus, the main insect pox virus used in locust biological control, was isolated by Henry Henry from the black-blooded locust Melanoplus sanguinipes in 1966. Since then, more than a dozen kinds of locust pox viruses have been discovered, such as The Siberian Locust Virus (Gomphoceru sibiricns EPV), the Asian Trolley Locust Virus (Oedaleus asiaticus EPV), the Italian Locust Virus (Calliptamus italicus EPV) and so on.
Poxviridae
Compared to pathogenic bacteria and fungi, locust pox viruses are intracellular parasites. Locust pox viruses are difficult to produce in large quantities and are the main problem limiting their practical control work.
Thankfully, however, this time the locusts will not pose a serious threat to our country. In the past 40 years, although locust plagues have occurred from time to time in some parts of China, they have not caused relocation hazards or serious economic losses.
It is important to note that locust plagues in Africa, Central and South Asia are caused by desert locusts. The main locust species distributed in China is the flying locust, so we don't have to worry too much.
But be prepared, after all, no one knows when the next disaster will strike and which species it will originate from. If we can make good use of the natural resource of microorganisms and solve the problems that nature brings to human beings, it will be the best of both worlds.
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Author: Guo Xiao Who would have thought that the way for our people to control locusts is to raise chickens and ducks... Observer Network