Some innovations in the use of pesticides in China

Pesticide use technology is a weak link in China's pesticide industry. The abuse of pesticides is not only wasteful, but the efficacy is not necessarily satisfactory. It also causes side effects such as adult animal poisoning, phytotoxicity, injury and other beneficial organisms, environmental pollution, and induction of pest resistance. On the other hand, for half a century, the vast number of peasant users and related scientific and technological workers in China have also made many innovations in the use of pesticides. Although this article is inevitably linked to a mile, there are still a few examples to illustrate.

First, the discovery of the internal action of organic pesticides

China's agricultural entomologist Qi Zhaosheng (1911-1999) discovered the root systemic action of the insecticide schradan during the training in the British Bunermen Company in 1949. This is the first time humans have discovered that some organic pesticides have a systemic effect.

Mr. Qi experimental design is a series of hydroponic broad bean seedlings. Under the premise of completely separating the stem from the root to eliminate the possibility of contact and fumigation, different doses of octaphosphorus may be added to the gradient in the culture water. (Editor's Note: Octaphosphorus can be used. It is miscible with water and stable in neutral aqueous solution.) Inoculation of soybean meal on the leaves of soybean seedlings to observe the toxicity in the roots. The results of the experiments in which the mortality of the soybean meal was significantly increased made the British colleagues very surprised. Subsequently, the patent application method for the pesticide was applied for this purpose.

It can be said that all kinds of pesticides, fungicides and herbicides in the world today use the technique of using various types of systemic effects, which are all based on the system.

Two, six six six powder treatment

In the early years of the founding of the People's Republic of China, the most important pest in agriculture in China was the rice aphid. Firstly, it is controlled with 6% hexachlorocyclohexane wettable powder, and the effect is excellent. Later, in the production practice, it was found that the use of 6% hexachlorocyclohexane powder was controlled, and the efficacy was comparable to that of the same preparation dosage of wettable powder, and the method of use could be simplified into toxic soil and pouring without any medical equipment. This is related to the ecological environment of rice fields, the morphological structure of rice plants, the pest habits, and the physicochemical properties of medicines. It can be considered that the non-wetting powder and its lipophilic hexachlorocyclohexane active ingredient tend to agglomerate at the junction of the rice stem and the water surface; the rough surface of the leaf sheath at the base of the rice stem and the gap between the longitudinal groove and the sheath and the stem Through the capillary phenomenon and evaporation of water, the active ingredient of BHC is continuously enriched inside and outside the sheath of the rice stem, and the hexagram also has partial systemic action; the hatching ants are hatched from the egg on the rice leaf. The silk must fall down to the surface of the water, climb to the stem base of the rice, and then climb to find the appropriate position of the stem-leaf sheath to drill into the stem. Anthills may be poisoned by exposure to 666 on the surface of the water, on the surface of the sheath and during the drill collar.

In the mid-1960s, the six powders (1% parathion 3% hexachlorocyclohexane powder) and the hexamethylene powder (1.5% methyl parathion 3% hexachlorocyclohexane powder) quickly replaced 6% six six six Powder is used to control rice blast and follow the latter experience to make a powder. In 1965, he was presided over by Huang Ruilun (1901 ~ 1975) and Wang Junkui in Xiangtan area. He organized farmers to carry out large-scale demonstration tests on rice aphids by using the six-powder poisonous soil. During the application process, the male and female applicators measured the ear lobe blood. The degree of inhibition of cholinesterase directly proves that this procedure does not cause acute poisoning to the applicant. Therefore, the application method of the six-powder powder and the six-powder powder is also a poisonous soil or a pouring of no need for a medical device.

It is well known that the processing of wettable powders requires the addition of relatively expensive wetting agents, high fineness requirements, and strict storage conditions, such as spray application and more labor, and greatly increase the cost of preparation and use than powder. From the 1950s to the early 1980s, the total amount of 666 powder, hexamethylene powder and hexahydrate powder used for the treatment of phlegm in the past 30 years has accumulated to 10 million tons. According to scientific experiments and production practices, powder can be used instead. The cost of wetting agents and preparations saved by wet powders was also a few hundred million yuan at the time, and it was basically converted into income from the increase in rice farmers' savings.

Third, the chemical control of the snail

Around 1960, the reduction of production caused by the hazard of the tussah was a common problem in several countries in Northeast Asia. The female flies produce the eggs on the leaf surface of the head of the normal feeding tussah. After the tussah swallows the flies, the latter hatches into the maggots in the digestive tract, drills through the digestive tract wall, and grows parasitic in the silkworm. When the larvae of the tussah are mature, the larvae of the old-fashioned fly larvae are detached from the silkworm body, so that the tussah can not be crusted and die. The tussah is stocked outdoors, and the fly larvae and the tussah are “mixed together”, which is very difficult to control.

Mr. Huang Ruilun proposed an academic viewpoint on the use of selective pesticides for chemical control. The specific content is that the virulence of the diptera insects is relatively high, and the lepidopteran insects are relatively safe. Under certain conditions of application and certain dosage, the tussah consciously takes the medicinal agent into the body, so that The concentration of the active ingredient in the body is not harmful to the older silkworm larvae, but is sufficient to poison the newly hatched or lower-aged fly maggots. Mr. Huang organized the strength, in addition to selecting the varieties of commercially available pesticides, and then targeted synthetic pesticide samples, and conducted technical research and chemical control demonstrations in the tussah area. In just two years, it was successful for production practice. At the beginning of the use of "Mongzao No. 1", the method of applying the sprayed leaf is equivalent to the use of the insect digestive tract to the systemic action of the drug; later, the "Mimrayus No. 3" was used to take the tussah "cutting" The method of applying the liquid medicine to the silkworm body is equivalent to the systemic action of the insect epidermis on the medicament. The latter efficacy is stable above 95%.

The practical application of this achievement has enabled the production of tussah in China to recover quickly and reach the highest level. The use technology of "silk-killing flies" only targets the fly larvae that have been parasitic to the tussah, and the safety of the fly-flying adults in the environment does not prevent the latter from controlling the pests such as the caterpillars and the gypsy moths in the forestry. This species is detrimental to its disadvantages. The successful experience of chemical control of tussah flies has been extended to the control of silkworms in the sericulture area, and has achieved good results. The use of insecticides that are selective for different insects to control the endogenous natural enemies of beneficial insects is the first of its kind at home and abroad.

The “silk-killing fly” was originally a confidential result, and gradually declassified. “No. 1” is Diguo, and “No. 3” is coumaphos.

4. Insecticide granules

The use of the technology was completed by research by Qiu Shibang and Zhou Darong.

The corn borer lays eggs on the corn leaves. Before the snoring, most of the early larvae are concentrated in the gaps of the leaves in the corn heart. After the corn is squirmed, a part of the corn mash is first hidden in the leaf sheath, and then drilled through the sheath to the stalk to continue to harm. This is a harmful habit of corn borer, which is determined to be the best time for chemical control and the best application site during the corn leaf.

Chemical control of corn mash, if the stems and leaves are generally sprayed, most of the medicinal agents are not hit. If the drug solution is used to fill the heart leaf, after the drug solution is dried, the drug film is formed only on the inner side of the heart leaf at the contact point of the drug solution. With the growth of the heart leaf and the outward extension, the inner side of the newly extracted heart leaf has no medicament at all. It is impossible to control the corn larvae that invade at this time. When the insecticidal granules with a certain effective period and sustained release effect are applied to the bell mouth of the corn heart leaf stage, the granules can roll down to the bottom with the growth of the corn, and the granules are always in the corn larvae. At this time, near the living position, and during the rolling process of the granules, a film of the drug can be left on the inner side of the heart leaf after application. After the corn is squirmed, most of the granules in the heart leaf are retained in the leaf sheath, which can kill the corn larvae that are harmed in the leaf sheath or drilled through the leaf sheath to the stalk. Of course, the granules thus used are not disintegrated with water, the granules should not be too light or the particle size is too small to prevent sticking to the leaves and not falling down.

The application period of granules for the control of corn mash shall be the end of heart. The first generation of corn blasts on spring maize has a peak of spawning in the middle of the heart, and the end of spawning lasts to the end of the heart. It can last up to one month before and after, and larvae invade the heart. Premature application, it is difficult to kill the larvae that occur late; the application of the late heart leaves can eliminate the larvae that are concentrated in the heart clump before and after. On the other hand, the early occurrence of aphids has a low survival rate, and the survival rate in the later stage is high and the damage is high. The focus of prevention and treatment should be in the later stage. Summer corn usually has two generations of corn borer, and the 2nd and 3rd generation eggs overlap. The end of the heart leaf is at the end of the 2nd generation of the egg and the age of the 3rd generation. At this time, the granule with longer duration is applied. Prevention and treatment of 2 generations, and treatment of 3 generations, including the larvae that hatch after the end of the heart leaf, play a role in preserving the ear. If you miss the end of the heart leaf and apply it again, not only because the plant is tall and difficult to operate, but also the corn starts to snoring, the granules can not be scattered into the tassel, and some of the larvae in the heart lobes will be drilled into the tassel, and the control effect is not good. Therefore, whether it is spring corn or summer corn, only at the end of the heart leaf prevention and treatment, the efficacy is significant, and corn production is also the highest.

The application technology has good efficacy, pharmacy, simple operation and almost no pollution to the environment. For decades, there have been many varieties of active ingredients such as DDT, parathion, carbaryl, methylisophosphorus, and phoxim.

5. Malathion oil agent for the control of pine caterpillars

In the early 1970s, pine caterpillars occurred in the suburbs of Beijing. Cheng Chunhe and Yu Shiqing studied their chemical control. Active ingredients were selected at a low price, low toxicity of malathion, the formulation selected oil, and the drug was selected at the time to introduce the domestic-style hand-held electric centrifugal mister. Dendrolimus is sensitive to malathion, malathion is easy to formulate oil, oil must be applied by mist equipment, mist must use low-toxic preparations, and mountain forest chemical control is better for non-water use. Oil mist is beneficial for infiltration in the canopy of forest trees and for hitting specific biological targets. These choices and their mutual cooperation are scientifically based.

Firstly, the pine caterpillars were collected from the control site, and the indoor virulence test was carried out to determine the lethal dose of the active constituents of malathion to the average body weight of the pine caterpillars, and then to adjust the content of the active ingredients in the oil, the physical and chemical properties of the oil, and Factors such as the speed of the foggy turntable, and finally the dose of the active ingredient in each of the average size droplets at the time of application is exactly the lethal dose of malathion to the average body weight of the pine caterpillar. In view of the long bristles on the surface of the pine caterpillar, the tip of the bristle is easy to capture the moving droplets due to the electrostatic effect, which makes the mist easy to hit the target of the insect. Then, if an average of each of the pine caterpillars catches a droplet, about half of the pest populations die; if the average pine caterpillar captures two or more droplets, the pest population is almost completely paralyzed. Of course, a considerable part of the mist droplets are captured by the tip of the pine needle, which is not wasted. It is also a target of hitting the application target. This part of the medicine can also play the role of pest killing and stomach poisoning within the effective period. Therefore, this technology has high efficacy in production practice, and the application efficiency is quite high, and the cost of medication is relatively low.

During the visit to Germany's Hoechst Company in the early 1980s, one of the company's experts detailed the use of endosulfan spray aircraft to kill cockroaches in Africa, using suitable solvents, auxiliaries and medical equipment to adjust to each liquid. The dose of the active ingredient contained in the droplet corresponds to the average lethal dose of each aphid in the group to be controlled. German friends have asked us whether China has such a high level of pesticide use technology. The author immediately pointed out that as early as ten years ago, Beijing used malathion oil to control pine caterpillars. It can be said that the seats were shocked at the time!

There are still many innovations in the use of pesticides in China. For example, in the development of prevention and control targets, China's first triadimefon to control various diseases in the late growth stage such as rice sheath blight, metalaxyl to prevent the onset of millet white, and Zhongdingling to control soybean dodder Wait.

Only a few examples detailed above can fully explain that there is much to be done to improve the level of pesticide use technology. Innovation in this area is as important as innovation in pesticide varieties. Of course, weapons must be well-purchased. If weapons are not used or used badly, they will only get twice the result. The high level of pesticide use technology means high efficacy, low pharmacy and side effects, that is, the use of as few remedies as possible, with the lowest possible cost of medication and the least cost of side effects, to achieve the highest possible benefits. This should be based on in-depth and high-level research on various related factors such as pesticides, dosage forms, medical devices, pests, crops, and farmland ecological environment, as well as toxicology, bioassay, and efficacy test. In addition, China has a vast territory. The agricultural crops, agricultural pests, farmland ecological environment, agricultural production mechanization and farmers' quality have their own characteristics. The pesticide use techniques in different regions often have differences.

The research on pesticide use technology is not only a matter of plant protection research and promotion department. The research and development and production units of pesticide varieties should also pay attention to it, or strengthen its own strength in this aspect, or cooperate or fund plant protection units for this purpose. This part of the cost can be fully incorporated into pesticide products. Among them. In fact, the improvement of the use technology of a pesticide variety has improved, which will certainly help the market development of this variety. As a general pesticide user, we should study basic knowledge of pesticides and basic knowledge of planting industry and its harmful organisms, and gain experience in practice in order to continuously improve the level of science and technology in the process of pesticide use, and continuously make progress and innovation.

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