According to media reports, while countries around the world are busy responding to the threat of a new coronary pneumonia epidemic, East African countries are facing a new problem-large-scale locusts are attacking again. The scale of this locust plague is 20 times that of the first disaster at the beginning of the year.

“Since the beginning of the year, the desert locust has swept Africa, West Asia, and South Asia. The Food and Agriculture Organization of the United Nations once again released information that the second wave of locust disasters has caused six countries in East Africa (Ethiopia) , Kenya, Somalia, South Sudan, Uganda and Tanzania) about 20 million people are in serious food crisis. In addition, Yemen has also been hit by locusts, and 15 million people in the country are facing the same situation. “Researcher, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, State Zhang Zehua, a scientist in the pasture industry technology system, said in an interview with a reporter from Science and Technology Daily.

A large-scale locust disaster occurred again in many countries, and Spodoptera frugiperda also threatened our country ’s food security. In this fight against pests, in addition to traditional chemical pesticides and other pest control measures, biological pesticides are gradually becoming a rising star in the insecticide industry.


Feeding fungi and causing locusts to get “flu”

So, what technologies are used in the design of biological pesticides and how do these pesticides eliminate locusts of?

“Biopesticides refer to living organisms and their metabolites, including microbial pesticides, plant-derived pesticides, natural enemy organisms, etc. Currently in the market of biological pesticides for controlling locusts, Most of them are environmentally friendly microbial pesticides, including fungi, bacteria, viruses, protozoa, etc. “Tu Xiongbing, an associate researcher at the Institute of Plant Protection of the Chinese Academy of Agricultural Sciences and secretary general of the National Innovation Alliance for Grassland Biological Disaster Prevention, told Sci-Tech Daily reporter.

These microorganisms come from nature. “For example, Metarhizium anisopliae, which we commonly use now, is an important entomogenous fungus, which is extracted from the body of locusts suffering from ‘influenza’. Compared with chemical pesticides, many biological pesticides have a slower effect. It usually takes 1 to 2 weeks to start working on pests. “Tu Xiongbing said.

In order to increase the speed and effectiveness of the prevention and control of these agents, researchers use aerospace mutagenesis, genetic engineering, molecular breeding and other technologies to increase their toxicity to locusts.

Tu Xiongbing said that locusts suffer from “fluid after eating or touching these fungi”Influenza”, and this “flu” will continue to reduce the reproduction rate, attack power and lifespan of locusts. From the current statistical data, the control effect of this control method can reach up to 8 to 10 years. There are also methods for natural enemies to control locusts. For example, in Inner Mongolia, the use of chickens and ducks to control locusts; in western Xinjiang, artificial nesting to attract pink starlings to control locusts has been successful, and has become a model for the prevention of locusts by natural enemies.


Has been used to control cotton and vegetable pests

“Any single technology cannot solve the problem of locust disasters, so it is necessary to combine biological control, chemical control, Several measures for ecological management to achieve long-term control of pest populations. “Zhang Zehua analyzed that, especially in medium and high density areas, continuous control measures based on biological pesticides can be used to make these microorganisms form disease epidemics in dense locust populations. By migrating and carrying each other, the locusts can be continuously controlled so that the disaster will not spread.

In addition to biological pesticides targeting locusts, what biological pesticides are scientists developing?

“In addition to fungi, bacteria and other microbial anti-locust insecticides, currently the market more biological insecticides are Bacillus thuringiensis, viruses, plant-based insecticides And other types. ”Tu Xiongbing introduced, among them, Bacillus thuringiensis insecticide, also known as Bt insecticide, is currently the most successful insecticide in the research, development and application of biological pesticides, accounting for about 90% of the total biological insecticides. More than 150% can control more than 150 kinds of lepidopteran pests.

“Bacillus thuringiensis can be used not only for pest control, but also for transgenic breeding techniques, such as the successful breeding of Bt transgenic cotton for insect resistance, effectively controlling cotton bolls Insect pests are widely used in cotton growing areas in China. “Tu Xiongbing said that nuclear polyhedrosis virus plays an important role in preventing and controlling vegetable pests such as beet armyworm, Spodoptera litura. There are also plant-based insecticides such as azadirachtin, matrine, rotenone, which have good control effects on different target pests such as aphids and diamondback moth.


Low toxicity or non-toxic, long duration of action

What are the main advantages of biological pesticides compared to chemical pesticides?

Zhang Zehua said that in comparison, biological pesticides have three major advantages, one is long validity. Compared with chemical pesticides, Biological pesticides have low or no toxicity, and last for a long time. For example, from 2003 to 2005, Taipusi Banner in Xilinguole League, Inner Mongolia, used Metarhizium anisopliae to control locusts for three consecutive years. Until 2016, surviving Metarhizium spores could still be detected in the soil. No locusts occurred in the area for 10 consecutive years.

Zhang Zehua pointed out that biological pesticides also have a major advantage, that is, they have good targets and strong selectivity. They are only effective for one or one type of pests, but not for non-target pests. At the same time, it is harmless to humans, birds, fish and silkworms. In addition, residue-free and environmentally friendly is also one of the advantages of biological pesticides. The dosage of bio-pesticides is relatively small, and pests are not easy to develop drug resistance. At present, there is no report on the resistance of pests after the use of bio-pesticides. And they are derived from soil, plants or insects in nature, so they can avoid the environmental pollution problems caused by chemical pesticides.

Zhang Zehua told reporters that taking microbial control of locusts as an example, before 2000, the average annual area of ​​grassland locusts in China exceeded 300 million mu, and biological control measures such as Metarhizium were adopted. Later, at this stage, the average annual occurrence area of ​​grassland locusts in China is controlled within 120 million mu. And the proportion of biological control has increased from 15.4% in 2003 to 60% now, making a positive contribution to protecting the grassland ecological environment.

“After practical tests, this biological control measure is harmless to the environment, widely accepted internationally, and has been widely promoted and applied in China. And it has also started to go abroad to serve countries along the “Belt and Road” such as Kazakhstan, Mongolia and Laos. ”Zhang Zehua said.


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What causes desert locust outbreaks year after year

“2019 The rain brought by the sub-cyclone provided favorable conditions for the propagation of locusts. The large-scale rainfall in March this year promoted the rapid incubation of locust eggs, which was an important cause of the desert locust outbreak. Burning wasteland, reclamation, abandoned farming, and idleness, leading to the destruction of the ecological environment, is the main reason for the desert locust outbreak. “Zhang Zehua analysis.

The wind field characteristics of the African continent provide unique conditions for the desert locusts to move, each year between the main breeding areas, from both sides of the Red Sea, the Horn of Africa to the Sahe Area, the center of the Sahara Desert, and the Nile River Basin, Tigris River, and YufaThe two river basins of the Ladi River and the Indus River Basin have moved cyclically, making desert locusts spread all over the African continent.

“Inadequate monitoring and inadequate prevention and control have led to successive outbreaks of desert locusts. Due to constant wars in Africa, insufficient monitoring technical strength, and poor communication of information, it is impossible to provide timely warning. Zhang Zehua said that there are more desert locust residues in 2019, which laid down “mines” for this year’s outbreak. The first wave of locust disasters failed to be effectively controlled, and the second wave of disasters mainly came from the first wave of desert locusts laying eggs The generations of locusts overlap seriously. There are both adults and nymphs in the family. The locusts are unearthed and the eggs are still hatching. The threat is becoming greater and more difficult to control. The desert locusts were allowed to reproduce for two generations without restraint, which led to the locust plague that would not be encountered in 2020.

As disasters have formed, there are not many options for prevention and control, excessive use of chemical pesticides, mass killing of natural enemies, and desert locusts that have lost their natural control are outbreaks.

(Original title Desert locust once again “groups” to attack the insecticide “star” bio-pesticide enlargement trick)