The role of virus pesticides in the biological control of cotton bollworm 1. Known methods for the prevention and control of bollworm: Since the beginning of human cultivation, humans have never stopped the fight against pests. Therefore, it is said that “the population of insects robs grain, and the population of insects robs cottonâ€. People's prevention and control of pests can be divided into several levels due to different measures: 1. Artificial insect catching 2. Chemical prevention After the World War II, chemical pesticides were used to control agriculture, forestry, animal husbandry, and sanitary pests, giving Humanity has brought significant economic benefits. However, since the 1960s, people have gradually realized that while chemical pesticides promote the development of human society, they also cause a series of problems: (1) Environmental pollution, residual poisons, and human and livestock are poisoned; (2) Pest resistance rises linearly , The rising drug use, the increasing prevention and control costs, and the constant efforts to develop new pesticides; (3) Killing natural enemies, destroying the ecological environment, causing re-emergence of pests and secondary outbreaks of pests. The emergence of these drawbacks has led people to re-emphasize the potential significance of biological control. 3. Comprehensive prevention and control Taking cotton bollworm as an example, the main methods are: (1) Agricultural control: Autumn plowing and winter irrigation, depressing the wintering base number, adjusting planting structure, strengthening field management, and selecting insect-resistant varieties or short-season varieties to avoid pest damage. (2) Using tactics and attractants to trap and kill: such as willow moths, light moths, and sex traps. (1) Reasonably apply chemical pesticides. 4. Biological control (1) Comprehensive use of various measures to protect and use natural enemies. For example, the natural enemies of Helicoverpa armigera are various parasitoids, ladybugs, florets, grasshoppers, spiders, etc. Many species can be artificially propagated and released into the field. By creating an environment favorable to natural enemies, pest populations can be controlled for a long period of time. . Reasonably arrange the planting structure, with little or no chemical pesticides to facilitate the breeding of natural enemies. One object drops one object and achieves the purpose of insect pests. (2) Prevention and control using biological pesticides 5. Natural prevention When integrated prevention and treatment have achieved results, especially after a period of biological control to restore the benign ecological cycle of farmland, natural enemies continue to effectively control pest damage, and no need to take measures (such as the application of pesticides, including virus microbial pesticides ) Control of pests can control pest damage below the economic threshold. Second, the status and role of viral pesticides in the comprehensive control or biological control of cotton bollworm 1. Insect viruses in the pest control is an important feature of their specificity of the host, in the integrated control system is a very good Control measures, choose to control pests (not all killing), the potential of beneficial insects in the entire ecosystem is being used. Viral pesticides participate in biological control is an ecological management method. The purpose is not to completely eliminate pests, but to control the population of host pests that the natural enemies depend on to be below economic threshold allowable levels, restore the benign ecological cycle of farmland, and finally obtain maximum benefits. . 2. The greatest benefit of using virus insecticides to control pests is that the target field where virus insecticides are sprayed not only has an infectious pathogenic effect on contemporary target pests, but also passes through the feces, adults, eggs and dead larvae of susceptible larvae. The corpses can infect the next generation of larvae. The virus will multiply in the host population and even spread to form an epidemic. The target host is at a low level for several years. 3. The virus pesticides have general biological pesticides that do not pollute the environment and do not harm natural enemies. Animals are highly safe and pests are not susceptible to resistance. In addition, recent studies have shown that the virus has a certain “weakening†effect on host insects, weakening the ability of the infected host to fly, decreased fecundity and hatchability, and degradation of other physiological functions, leading to increased natural mortality rates for some pesticides. The resistance is also significantly reduced, which is beneficial to the comprehensive 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 major issues facing humanity in the 21st century. The core connotation and basic features of biological control are its compatibility with the ecological environment and sustainable development. The unity. Biological control is the inevitable development of human society's advancement of science and technology. Insect insecticide is a powerful weapon for modern agricultural engineering that meets the requirements and development of the times and targets organic food.