Garden plants not only improve the ecological environment of urban and rural areas and beautify people's lives, but also achieve good economic and social benefits. The pest damage not only affects the construction of urban gardens, but also causes great economic losses. With the development of landscaping, the problems of pest damage and new technologies have become increasingly prominent. Traditional chemical control not only pollutes the environment and destroys the ecological balance, but also poses a threat to human health, seriously affecting the landscaping and beautification functions. In recent years, with the improvement of people's awareness of environmental protection, more and more biological control methods are required to prevent and control garden plant pests.

Pest biological control is the science of using natural enemies and biologically active substances to control pests. There are many types of natural enemies of pests. It can be said that, except for humans, all creatures that feed onpests or pose a threat to pests are natural enemies. However, the natural enemies used in biological control are mainly predatory natural enemy insects, parasitic natural enemy insects, and pathogenic insects. There are three major categories of natural enemies of disease microorganisms. There are also many types of biologically active substances. However, four categories of insect hormones, plant active substances, antibiotics and genetically engineered plants are mainly used in biological control.

In the future biological control of pests, in addition to actively discovering new biological control strains and vigorously developing special management of natural enemies, traditional biological control is still the main research direction of biological control. The application of biotechnology in the field of biological control has made great progress and has become a hot spot in the field of scientific research on biological control. With the expanded application of electronic technology and data processing methods, biosynthetic methods will surely become feasible methods in the design of biological agents. Plant insecticides and insect hormones will also become an important aspect of biological control, and all aspects of biological control have good development prospects.

1 Traditional biological control is still the main research direction of biological control

The introduction of natural enemies has been carried out for more than 100 years, and its full potential has not yet been realized. The use of traditional biological control is an effective means to control foreign pests. According to statistics, since 1900, 70% of pests in the Netherlands are foreign. There were at least 837 species of alien insects established in the United States from 1920 to 1980, of which 10% have become serious pests. It is estimated that there are 500,000 species of parasitic Hymenoptera in the world, but only less than 50,000 species have been described. The potential for biological control is less than 10%. The success of traditional biological control is directly proportional to the efforts made by the introduction of natural enemies. my country has established natural enemy exchange relations with more than 20 countries and regions. The aphid bee and the aphid gall midge were introduced from the UK and Canada respectively. These two natural enemies have shown good control power in the control of whiteflies and aphids in Chinese garden plants.

As people become more aware of natural enemies and improve their selection, production and transplantation techniques, the success rate may actually be greater than what has been in history. Through greater efforts from all aspects of society, traditional biological The chance of success in prevention and control will increase significantly. Of course, it should be recognized that biological control is an important part of integrated pest management (IPM). The greatest contribution to IPM is not through introduction or inoculation, but the protection and utilization of local natural enemies in the garden plant system. With the passage of time and the accumulation of knowledge and experience, natural biological control will also be better applied.

2 Utilization of insect pathogenic microorganisms

There are more than 1,000 species of insect pathogenic microorganisms. These microorganisms are harmless to humans, animals and plants, and can be used to control pests. The use of microorganisms to control pests has the advantages of wide application range, long-lasting virulence and convenient use. Many cities in my country have accumulated rich experience in carrying out microbial pest control.

3 Utilization of insect viruses

Viruses are organisms smaller than bacteria, and they are highly specialized and cannot survive without the host. They must be cultured in vivo. There are more than 500 kinds of insect viruses that have been discovered. my country is rich in insect virus resources. 234 pathogenic viruses have been isolated from 33 species of insects in 7 orders, providing precious natural resources for the development and production of insect virus insecticides. There are two main types of insect viruses used to control pests, namely nuclear polyhedrosis virus and granulovirus. These two types of viruses can control major pests such as aphids, canopy caterpillars, loopers, tussock moths, pine caterpillars, nest moths, diamondback moths and cotton bollworms.

4 Development prospects of plant pesticides

Plant insecticides are insecticides made by using certain parts of plants with insecticidal activity or extracting their active ingredients. It is a safe and economical insecticide developed on the basis of research on the effective ingredients of insecticidal activity possessed by some plants. It is a plant biochemical substance. At present, my country has developed and registered more than 20 varieties, mainly including neem, chrysanthemum, anisin, pyrethrum, veratrine, nicotine, matrine, celangulin, cineole, etc. . It is used to control aphids, caterpillars, looper, tussock moths, pine caterpillars, nest moths, small curlers, cutworms, spider mites and other pests.