For a long time, people have relied on a large number of pesticides to control harmful organisms. The first pollution of the ecological environment and agricultural products such as the atmosphere, waters and soils, especially the pesticides in the first sector, are potentially carcinogenic, teratogenic and catastrophic, threatening people's health. The uncontrolled abuse of chemical pesticides also affects the survival of beekeeping, sericulture, fisheries and the survival of wildlife resources. The second is that while chemical pesticides kill pests, they also kill a large number of non-control objects, especially natural enemies that control the development of pests, destroying the ecological balance and causing the re-increase of harmful organisms. The third is that the resistant population of pests has increased exponentially, which has greatly reduced the control effect of some pesticides and rendered them ineffective. Therefore, we must promote scientific use of drugs, not only to fully play the role of chemical pesticides, but also to minimize its adverse effects.
First, the fair mix of pesticides: Scientific and reasonable mixing of pesticides is conducive to the full application of pesticide formulations. At present, there are two kinds of mixing methods. First, two or more kinds of pesticide raw materials are mixed and processed to make a compound preparation, which is commercialized by a pesticide company and put on the market, and the prevention and control staff does not need to prepare again. The second is the use of on-site mixing. The prevention and control staff are very vulnerable to the actual needs of the prevention and control of the upper body, and two or more kinds of pesticides are mixed and applied.
Second, grasp the appropriate period of application: The purpose of determining the appropriate period of application is to obtain the maximum economic benefit of prevention and control with a small amount of pesticides. Generally consider three aspects. First, according to the dynamics of the pests and beneficial organisms in the field, avoid the sensitive period of natural enemies to pesticides, and choose to apply the drugs to the natural enemies with no or little influence on the harmfulness of the pests. Second, we must thoroughly understand the biological characteristics, characteristics and occurrence rules of the target, and seek the most vulnerable period. In general, the pests are weak in resistance at the young age, and some pests are clustered at an early stage. Many drillworm pests and underground pests have to start dip and enter the soil at a certain age, and the effect is obvious. For the disease, it is generally necessary to grasp the application in the early stage of the disease, because once the bacteria invade the plant, the agent is more difficult to exert. For weeds, it is best to apply the herbicide during the period when weeds are most sensitive to herbicides. Sometimes it is most beneficial in weed seedlings; sometimes it is often done before or before germination in order to avoid harming crops. The third is to apply the drug at the most vulnerable stage of the crop.
Third, strictly in accordance with the prevention and treatment indicators: Because of the comprehensive effects of various factors in the farmland ecosystem, the number of pests is always kept within a certain range, always fluctuating at a certain level, neither increasing indefinitely It will not be reduced indefinitely. If the number of pests is kept in a low-density range, it will not cause economic losses, but also benefit the reproduction of natural enemies, making it a powerful factor in controlling harmful organisms, which is very beneficial to human beings. Therefore, we must strictly follow the prevention and control indicators formulated by local governments. Only when the number of pests is close to the level of economic damage, we must take chemical control measures to control them. It is necessary to strive to achieve the rule of treatment that can be ruled; to be able to cure the disease, not to rule, to reduce the area of ​​application and the number of applications. In this way, on the one hand, it can save pesticides, reduce costs, reduce the pollution of pesticides to the environment and agricultural products, and at the same time, expand the protective surface of natural enemies and reduce the killing effect on natural enemies.
Fourth, the use of appropriate dosage: In the amount of dosage, it is necessary to change the habit of pursuing a high dose of more than 99% in the past. Choose the right dose. One is the appropriate concentration of the liquid or powder, and the other is the appropriate amount per unit area. Generally speaking, the higher the concentration, the greater the effect, but exceeding the effective concentration not only causes spreading, but also may cause phytotoxicity; below the effective concentration, it does not achieve the purpose of prevention and control, and the trace use of toxic substances is even harmful. The organism has a stimulating effect. If the dosage per unit area is too much or insufficient, the same adverse consequences as described above will occur. Therefore, before the application of the drug must be determined according to the concentration and dosage.
V. Disabling high-toxic and high-residue pesticides: Organochlorine pesticides such as DDT and BHC are highly persistent in the environment, and are easy to concentrate through the food chain, enriched in food, and harm human health. Most of them are non-selective. A broad-spectrum insecticide that acts as a killer against natural enemies. Organic mercury preparations such as Sai Li San and Xi Li Sheng are highly toxic to mammals, and are also susceptible to phytotoxicity to plants. Pesticide talents have been phased out in countries around the world. At the same time, countries are also banned from using long-acting pesticides and highly toxic pesticides on crops such as grains, vegetables, tobacco, fruits and medicines as well as in waters. Highly toxic pesticides such as phorate and carbofuran are used only for the treatment of seeds, or in granules in the soil, and not for spraying, to ensure the safety of the application staff. On the basis of understanding the dynamics of pesticides on crops, the number of days of crop harvesting at the last application interval was also delineated to avoid poisoning of humans and animals.
Sixth, rotation of drugs: a long-term repeated use of a pesticide for a pest, kill individuals with sensitive genes, retain individuals with resistance genes, from generation to generation, gradually form individuals and populations with significant resistance The infectivity of this pesticide is at a very low level, and the control effect is greatly reduced. Moreover, there is also the phenomenon of "interactive resistance", that is, a pest is resistant to a certain agent, and is also resistant to certain agents that have been used. One of the effective ways to overcome and delay the resistance is to alternate the application of pesticides. In general, it is possible to delay the occurrence of drug resistance by alternately applying two or more kinds of agents having different action mechanisms. However, it is necessary to pay attention to the cross-resistance problem of this pest, and choose to use the drug without cross-resistance alternately, otherwise, the purpose of preventing drug resistance cannot be achieved. A harmful biological strain that is resistant to a certain drug is more sensitive to another drug. This phenomenon is called “negative cross-resistanceâ€. If it is used in rotation, a pesticide with negative cross-resistance is selected. It is more effective to replace pesticides that have become resistant to harmful organisms.
The types of mixed pesticides include insecticide plus synergist, fungicide plus herbicide, fungicide plus fungicide, herbicide plus herbicide, insecticide plus fungicide, insecticide plus herbicide. Mixed use can expand the types of control objects, can overcome the resistance of harmful organisms to pesticides; achieve a multi-drug treatment; can exert synergistic effects; can extend the life of pesticides of old varieties; can also reduce the cost of prevention and treatment.
However, there is no rigorous scientific position when mixing. The current distribution of the field should adhere to the principle of mixing and testing first. Generally, the following points should be considered, that is, the toxicity to humans and animals should not be increased, or the multiplication ratio should be small; it should be safer without increasing the phytotoxicity to crops; the synergistic effect should be produced after the mixing of two or more pesticides instead of Reduction effect; should not produce flocculation and a large amount of precipitation; acid-base reaction should not occur, that is, acid decomposition or alkali decomposition.
This article is published by the China Pesticide Network , please indicate the source.
Reinforced Aluminum Foil Insulation
Non Woven Fabrics,Rock Wool,Glass Wool
Myriad Corporation , http://www.wxfoil.com