Definition of biocontrol bacteria

The biological control effect is unstable, the application scope is narrow, the geographical adaptability of biocontrol bacteria is low, and the production, transportation and storage of biocontrol bacteria need strict conditions, so its control benefit is lower than that of chemical control.

Biological control has many advantages over chemical control, such as safety to human beings and natural enemies, good compatibility with the environment, long-term stable control of harmful organisms after biological colonization, and rich beneficial biological resources for development. Its disadvantages are that the effect of pest control is easily influenced by environmental factors, which is not as effective as chemical control, and it is difficult to artificially propagate beneficial organisms and apply technology, and there are few natural enemies in commodity production, and the application scope is narrow.

Biological control refers to various measures to control plant diseases by using beneficial organisms. Up to now, beneficial microorganisms, also known as antagonistic microorganisms or biocontrol bacteria, have been mainly used.

Biological control measures can reduce the inoculation amount of pathogenic bacteria, reduce the pathogenicity of pathogenic bacteria and inhibit the occurrence of diseases by regulating the microbial environment of plants.

Biological control is mainly used to control soil-borne diseases, leaf diseases and postharvest diseases. Because the biological control effect is not stable enough, the application scope is narrow, the geographical adaptability of biological control bacteria is low, and the production, transportation and storage of biological control bacteria have strict requirements on conditions, and its control benefit is lower than that of chemical control. Now it is mainly used as an auxiliary control measure.

Biological control mainly uses various adverse effects of beneficial microorganisms on pathogenic bacteria to reduce the number of pathogenic bacteria and weaken their pathogenicity. Beneficial microorganisms can also induce or enhance plant diseases, and inhibit the occurrence of diseases by changing the relationship between plants and pathogenic bacteria.

The adverse effects of beneficial microorganisms on pathogens mainly include antibiosis, lysis, competition, heavy parasitism, predation and cross protection.

Beneficial microorganisms produce antibacterial substances and inhibit or kill pathogenic bacteria, which is called antibacterial action. For example, Trichoderma viride produces two antibiotics, namely colloid toxin and green pigment, which antagonizes rice sheath blight and other pathogenic bacteria. Some antibacterial substances have been artificially extracted and produced as agricultural antibiotics. Jinggangmycin developed in China is a glycoside compound produced by Streptomyces hygroscopicus var. It has been widely used to control rice and wheat sheath blight.

Cross-protection refers to the phenomenon that inoculation of weakly virulent microorganisms induces plant disease resistance, so as to resist the infection of virulent pathogens, and it also belongs to the category of biological control.

There are two basic measures for biological control of plant diseases. One is to introduce a large number of exogenous antagonistic bacteria, and the other is to adjust environmental conditions to make the existing beneficial microbial population grow and show antagonistic activity.

Attenuated mutants of tobacco mosaic virus N 1 1 and N 14 and attenuated strain S-52 of cucumber mosaic virus were obtained by nitrite mutation in China. Inoculating attenuated strains with pepper and tomato seedlings by pressure spraying method can induce mutual protection, which has been used for field control of virus diseases.

In order to give full play to the efficacy of pesticides and achieve safety, economy and high efficiency, rational use of pesticides is advocated.

Any pesticide has a certain scope of application, and it is necessary to treat diseases.

It is necessary to scientifically determine the dosage, application cycle, application frequency and interval days.

It is advocated to mix pesticides reasonably, apply pesticides at one time, and control various pests and diseases at the same time, so as to reduce the application times and control costs.

Improper use of chemicals will damage plants, which is called phytotoxicity. Acute phytotoxicity occurs within a few hours to a few days after application, and chronic phytotoxicity occurs after a long time.

Long-term continuous use of a single fungicide will lead to drug resistance of pathogenic bacteria and reduce the control effect.

Pesticides can enter the human body through the skin, respiratory tract or oral cavity, causing acute or chronic poisoning.

Do not use highly toxic and high-residue pesticides prohibited by the state, and strictly abide by the allowable pesticide residue standards and safe use intervals.