The role of viral pesticides in the biological control of cotton bollworms 1. Known methods for the control of cotton bollworms:
The struggle of human beings from the beginning of farming has never stopped, so there is a saying that "the insects catch the grain and the insects catch the cotton." People's control of pests can be divided into several levels due to different measures:
1. Artificial catching insects 2. Chemical control After the Second World War, chemical pesticides brought significant economic benefits to humans due to the prevention and control of agriculture, forestry, animal husbandry and health pests. However, since the 1960s, people have come to realize that while chemical pesticides promote the development of human society, they also cause a series of problems:
(1) Environmental pollution, residual poisons, poisoning of humans and animals;
(2) The resistance of pests has risen steadily, the dosage of drugs has been rising, the cost of prevention and control has been increasing, and it is busy to develop new pesticides endlessly;
(3) Killing natural enemies, destroying the ecological environment, causing re-emergence of pests and secondary outbreaks of secondary pests.
The emergence of these drawbacks has led people to re-emphasize the potential significance of biological control.
3. Comprehensive prevention and control Take the cotton bollworm as an example, the main means are:
(1) Agricultural control: autumn tillage and winter irrigation, lowering the winter base, adjusting planting structure, strengthening field management, and selecting pest-resistant varieties or short-season varieties to avoid pest damage.
(2) Using tropism and attractants to trap: such as the willow moth, light moth, sexual attractant trap.
(3) Rational application of chemical pesticides.
4. Biological control (1) Comprehensive use of various measures to protect and utilize natural enemies.
There are a variety of natural enemies of cotton bollworm as parasitic wasps, ladybugs, flower bugs, lacewings, spiders, etc., it can be many types of artificial breeding to field release, and through the creation of an environment conducive to predators, can control the number of long-term pest population . Reasonable arrangements for planting structure, little or no Shi Shi multiply beneficial predators of chemical pesticides. A thing down, made of insect pest to achieve the purpose.
(2) Prevention and control of the use of biological pesticides 5. Natural control When comprehensive prevention and control have achieved results, especially after the biological control has restored the benign ecological cycle of farmland, natural enemies continue to effectively control pest damage, and no measures are required (such as pesticide application, including viral microbial pesticides). Controlling pests can control pest damage below the economic threshold.
Second, the status and role of viral insecticides in the comprehensive control or biological control of cotton bollworm 1. The important feature of insect viruses in the prevention and control of pests is their specificity to the host, which is an ideal in the integrated control system. Control measures, choose to control pests (not all pass kills), the potential of beneficial insects in the entire ecosystem is used. The participation of virus pesticides in bio-control is an ecological control method. The purpose is not to completely eliminate pests, but to control the population of host pests on which the natural enemies survive to be below the economic threshold, restore the benign ecological cycle of farmland, and finally obtain the maximum benefit. .
2. The biggest advantage of using virus insecticides to control pests is that the target field sprayed with viral insecticides not only has an infection-causing effect on contemporary target pests, but also passes the feces, adults, eggs and dead larvae of susceptible larvae. The corpse can infect the next generation of larvae, the virus proliferates in the host population, and even spreads epidemics, leaving the target host at a low level for several years;
3. Viral insecticides have the advantages that general biological pesticides do not pollute the environment, do not harm natural enemies, are highly safe for humans and animals, and are not susceptible to pests. In addition, recent studies have shown that the virus has a certain "weakening" effect on host insects, which can weaken the ability of infected host to fly, reduce the rate of egg production and hatching, and degrade other physiological functions, causing the natural mortality rate to rise. The resistance is also significantly reduced, which is advantageous for the integrated control of pests.
4. People have fully realized that the protection of the ecological environment and the sustainable development of agriculture have become the two central problems facing humanity in the 21st century. The core connotation and basic characteristics of biological control are its integration with the ecological environment and sustainable development. Unity. Biological control is the inevitable development of science and technology in human society. Insect virus insecticides are powerful weapons for modern agricultural engineering that meet the requirements and development of the times and target organic food.
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