Basic knowledge of pesticide purchase and use

Pesticide refers to a chemical used to prevent, destroy or control diseases, insects, grasses and other harmful organisms that endanger agriculture and forestry, as well as chemicals that purposely regulate the growth of plants and insects, or substances derived from organisms and other natural substances. Or a mixture of several substances and their preparations.

Qualified pesticide products must have “three certificates”. The “three certificates” of pesticides refer to the pesticide production permit, pesticide standards and pesticide registration certificate. The “three certificates” are issued on a product-by-product basis, that is, each pesticide product and the same pesticide product are produced by different manufacturers, and each has its own “three certificates”.

First, the meaning of fake pesticides and inferior pesticides

1. The name of the active ingredient contained does not match the approved label;

2. Pretending to be a pesticide with a non-pesticide or posing as a pesticide with other pesticides;

3. Counterfeiting, forging or transferring pesticide registration certificates or pesticide labels;

4. The State officially announces pesticides that are prohibited from being produced or withdrawn (because they are no longer available as pesticides).

Inferior pesticides are one of the following:

(1) The product quality is seriously inconsistent with the pesticide product standard requirements;

(2) Exceeding the warranty period and losing the value of use; or using it for a limited time without indicating the expiration time;

(3) mixed with harmful components that can cause phytotoxicity or other losses;

(4) The package or label is seriously damaged.

Second, the shelf life of pesticides

The period from the date the factory produces the packaging to the last date without degradation and efficiency is called the shelf life. During the shelf life, the quality of pesticide products should not be lower than the technical indicators specified in the quality standards. Users should be satisfied according to the application of pesticides on the pesticide label, application method, concentration (or dosage). The control effect does not cause phytotoxicity.

Third, the cause of changes in the quality of pesticides during storage and transportation

A chemical pesticide is a chemical synthesized by chemical reaction of two or more substances under certain conditions.

Since pesticides are a kind of chemical substance, of course, they are also affected by natural factors such as light, heat and humidity, and the original performance changes, and even deteriorates. There are many factors that cause changes in the quality of pesticides during storage and transportation. The main ones are:

1, temperature. The higher the temperature, the greater the impact on the quality of the pesticide. In addition, the temperature below zero is also affecting the quality of pesticides, especially liquid pesticides, which are prone to crystallization or precipitation, reducing emulsifying power and reducing efficacy.

2, humidity. Too much humidity in the air can cause changes in the quality of the pesticide and affect the efficacy. In particular, when the powder or the wettable powder pesticide absorbs the moisture in the air, it tends to agglomerate or agglomerate the powder, thereby reducing the fluidity of the powder or the suspending rate of the wettable powder, thereby reducing the control effect.

3, lighting. Light is also an important factor in the deterioration of pesticides. It can promote the photochemical reaction of active ingredients in pesticides and decompose the active ingredients.

4. Quality of raw materials. The quality of raw materials is high, and the content of pesticides produced is also high; the quality of raw materials is low, not only the low effective ingredients of the finished products, but also a lot of impurities, increasing the toxicity of pesticides to humans and animals. This is most evident in the synthesis of organophosphorus pesticides.

5. Pesticide packaging. In particular, the sealing of emulsifiable pesticides should be strict. If the packaging is not tight and not good, it will easily cause the product to absorb moisture and decompose and volatilize, and it is easy to contact with the oxidative decomposition of air to cause quality changes. This is the case with omethoate.

According to some physical and chemical properties of pesticides, in addition to temperature, humidity, sunlight, air, pressure, etc. have an impact on the quality of pesticides, as well as acid and alkali have a great impact on the quality of pesticides. Therefore, most pesticides cannot be contacted with acids or alkaline substances during storage.

4. Pesticides cannot be stored in the same warehouse as chemical fertilizers.

There are more varieties of chemical fertilizers, more varieties of pesticides, and their properties are different. For example, chemical fertilizers are volatile, explosive, acidic, and alkaline. Pesticides are also easily decomposable, flammable, explosive, and toxic. So can't put it in stock.

5. Identify the quality of pesticides and scientifically purchase pesticides.

1, powder

(1) Appearance. The appearance of the powder should be loose powder and no agglomerates.

(2) Hygroscopicity. Before taking the powder to measure the hygroscopicity, first check whether there is any moisture outside the powder packaging paper bag. If there is, it is of course a hygroscopic performance. Then take a little powder from the bag and pour it on a piece of white paper. Pick up the white paper and use your thumb and forefinger to pinch it outside the paper. If it sticks to a piece, it indicates that the powder has absorbed moisture. If the powder is dusting. The use indicates that the quality is not good; if it is still loose fine powder, it indicates that it is a good powdering agent. The hygroscopicity of the wettable powder is larger than that of the general powder, but the medicament is used for watering, and the effect of hygroscopicity on it is smaller than that of the powder for dusting. However, moisture absorption is not always a good thing, because pesticides are prone to deterioration after being wet.

2, wettable powder

(1) Appearance. It should be a very fine loose powder, no clumps.

(2) Wetting. Use a large glass bottle filled with water, then gently pour a spoonful of wettable powder from the top onto the water with a small spoon. After 2 minutes, if it can be completely wet and gradually sink, it is moist. A wettable wettable powder; if the powder is still floating on the water, it is a poorly wettable agent. In this way, it is also possible to distinguish which one is a wettable powder, which is a powder for dusting, and a wettable powder which is easy to wet. Generally the powder is not wetted.

(3) Suspension. Block the wetted glass bottle above, shake it back and forth 30 times, then place it for 10 minutes and take a look. If the liquid is still turbid, when the powder at the bottom of the bottle is not much, it is a wettable powder with better suspension; if more than half of it has been sunk or the liquid is nearly clarified, the suspension performance is not good; if all the powder When it has sunk to the bottom of the bottle, it is a wettable powder with poor suspension; if the agent is condensed into a mass, it means that it is not a good wettable powder.

3, emulsifiable

(1) Appearance. First look at the emulsification in the vial has been layered, and then see if it is already turbid, whether there is crystallization, any emulsification that is not stratified, not turbid and not crystalline is a good emulsifiable concentrate. The emulsified oil which has stratification, turbidity or crystallization is already deteriorated, and the effect is poor when used. Of course, if the emulsifiable concentrate is placed at a very cold temperature, crystals are found, and when it is dissolved at room temperature, it cannot be considered to be deteriorated.

(2) Emulsifying properties. Pour a volume of emulsified milk into 19 parts of water, shake it for 30 times after mixing, then let it stand for half an hour to see if there is any oil or paste floating on the water, then take a look at the bottom. There is no sediment, and if not, it indicates that the agent has a good emulsifying power. When measuring emulsification, if the emulsifiable concentrate placed in the water can spread out quickly, turning white into the best emulsifiable concentrate, this kind of emulsifiable concentrate that can spread out without stirring, also called a strong diffusion emulsion. If there is obvious sediment, or there is oil slick on the water surface, the cream is a emulsification with poor emulsifying properties.

4. Suspending agent. The suspending agent should be a slightly viscous, flowable suspension with a very small viscosity and uniformity. If stratification occurs due to long-term storage, it can still be regarded as a qualified product if it can be restored by hand shaking. If it cannot be re-formed into a uniform suspension, the sediment at the bottom will not shake and the suspension performance will be poor.

Sixth, the problem of mixed use of pesticides should pay attention to

1. It is necessary to clarify the purpose of mixing pesticides, and it cannot be mixed for mixing. The mixed use of pesticides should achieve the purpose of increasing efficiency, treating and expanding the scope of prevention and control. If the above objectives are not achieved, they should not be mixed. Otherwise, it will cause waste, will not receive the desired effect, and even cause phytotoxicity.

2. No adverse chemical or physical changes should occur after the pesticide is mixed. If the agent is not decomposed after mixing, the emulsifiable concentrate is not destroyed, and the suspension does not cause flocculation or a large amount of precipitation, and can be used in combination.

3. After mixing, the mixed liquid (medicine powder) should not cause phytotoxicity to crops. If there is phytotoxicity, it cannot be mixed with each other.

4, after the mixing of the drugs, it should be to improve the efficacy of the mixed liquid, at least should not reduce the efficacy, that is, to increase efficiency after mixing.

5. After the drug is mixed, the acute toxicity of the mixture is generally not higher than the original toxicity, that is, it cannot be poisoned.

Seven, the cause of the phytotoxicity

1. Misuse on sensitive crops. Most pesticides have their corresponding sensitive crops to prevent misuse.

2. Use the drug during the sensitive phase of the crop. The different resistance stages of crops have different resistance to pesticides. Generally speaking, the seed resistance is the strongest. Most crops are susceptible to phytotoxicity at the seedling stage and flowering stage. The booting stage of gramineous crops is sensitive to the medicament, and the pesticides are applied from the tillering stage to the booting stage. Poor sensitivity.

3, high temperature, humidity, strong sunshine and easy to produce phytotoxicity. For example, stone sulphur mixture is highly susceptible to phytotoxicity when used at temperatures above 32 °C. There are also a small number of agents that are susceptible to phytotoxicity when used at low temperatures.

4, too much drug, too high concentration or improper application methods. The tolerance of crops to pesticides is limited. If the dosage is too high or the concentration is too high, the crops will cause phytotoxicity.

5. Improper mixing. Each pesticide has a certain amount of combining ability, and misuse often causes phytotoxicity.

Eight, the main symptoms of crop phytotoxicity

1, spots

Spot poisoning mainly occurs on the leaves, sometimes on the stem or fruit epidermis. Common brown spots, yellow spots, dead spots, net spots and so on. The spots of the drug are different from those of the physiological disease. The distribution of the drug spots on the plants is irregular, and the whole plot is light and heavy. The lesions usually occur in general, and the sites where the symptoms appear are more consistent. The spots of the drug spots are different from those of the fungal diseases. The size and shape of the drug spots are large, and the lesions have the center of the disease and the shape of the spots is relatively uniform.

2, yellowing

Yellowing can occur in the stems and leaves of plants, and more yellowing occurs in the leaves. The main cause of yellowing is that pesticides hinder the normal photosynthesis of chlorophyll. The mild appearance is yellowing of the leaves, and the severe occurrence is yellowing of the whole plant. Leaf yellowing has the yellowing of the heart leaf and the yellowing of the base leaf. The yellowing caused by phytotoxicity is different from the yellowing caused by lack of nutrients. The former often turns from yellow leaves to dead leaves, and there are many sunny days. The yellowing is rapid, the rainy days are more, and the yellowing is slower. The latter is often associated with soil fertility, and the whole plot of yellow seedlings is consistent. Compared with the yellowing caused by the virus, the yellow leaves of the latter often have a greenish appearance, and the diseased plants exhibit systemic symptoms, which are mixed with healthy plants in the field.

3, deformity

Malformations caused by phytotoxicity can occur in the stems and roots of crops, and common are rolled leaves, clumps, swollen roots, deformed ears, and deformed fruits. The malnutrition of the drug is different from the malformation of the virus. The former is common and the local symptoms are manifested on the plant. The latter often occurs sporadically, showing systemic symptoms, often mixed with broken green veins and wrinkles.

4, withered

The phytotoxicity of the wilting often shows symptoms throughout the plant, mostly caused by herbicides. The wilting caused by phytotoxicity is different from the wilting symptoms caused by the disease in the plant. The former has no morbidity center, and most of the process is slow, first yellowing, post-mortem, and no browning of the rhizome. The latter is mostly rhizome conduction. The tissue is blocked. When the sunlight is irradiated and the amount of evaporation is large, the first wilting occurs, and then the green dead seedlings are lost. The root catheter often has browning.

5, growth stagnation

This kind of phytotoxicity inhibits the normal growth of crops and slows the growth of plants. This phenomenon is generally caused by herbicide phytotoxicity, but it is only different. The stagnation caused by phytotoxicity is more complicated with the stiffness and deficiency of physiological diseases. The former is often accompanied by symptoms of drug touch or other phytotoxicity, while the latter is characterized by poor root growth and dysfunction. The color is yellow or dark green.

6, infertility

Infertility is a reflection of a phytotoxicity caused by improper use of crops during reproductive growth. Infertility caused by phytotoxicity and infertility caused by climatic factors are different. The former is a whole plant infertility, sometimes it is partially strong, but mixed with other phytotoxicity symptoms; and the climate-induced infertility has no other symptoms, and rarely occurs all. Infertility phenomenon.

7, shedding

Most of this phytotoxicity is manifested in fruit trees and some dicotyledons, with symptoms such as falling leaves, falling flowers, and falling fruits. Pay attention to the defoliation, falling flowers, fruit drop caused by phytotoxicity and the defoliation, falling flowers and fruit falling caused by the atmosphere or cultivation factors. The former is often accompanied by other phytotoxicity symptoms, such as yellowing, dry coke, and then falling leaves. The latter is often associated with severe weather and often occurs during high winds, heavy rains, and high temperatures. Cultivation factors should be caused by lack of fertilizer or excessive growth, causing falling flowers and falling fruits.

8, inferior fruit

Such phytotoxicity is manifested on the fruit of the plant, which makes the fruit smaller, the fruit surface is abnormal, the quality is deteriorated, and the edible value is affected. The inferior fruit caused by phytotoxicity is different from the inferior fruit caused by the disease. The former has only symptoms, no symptoms, and sometimes other symptoms of phytotoxicity; the latter has symptoms and many symptoms, and some viral diseases show systemic symptoms. Or does not show other symptoms.

Nine, pay attention to the purchase of pesticides

1. See the product introduction. Counterfeit and inferior pesticides are often illegible, strange and typo, unscientific exaggerated effects, and incomplete content.

2. Look at the registered trademark. First, there is a "registered trademark", and second, there is a "trademark pattern", both of which are indispensable. Counterfeit pesticides often have no trademark or trademark design.

3. Look at the two certificates. The two certificates refer to the “Pesticide Registration Certificate”, “Production License” or “Practice Certificate”. No. 1 refers to the "Product Standard Code". You can buy with the pesticides on the label with two certificates.

4. Look at the expiration date and production batch number. The "validity period" is the maximum period of validity of the pesticide from the beginning of production and packaging. The “production batch number” is the batch number of the year, month, day and day of the pesticide production. Pesticides that exceed the expiration date cannot be purchased.

5, look at the name of the factory, the site. The name and address of the factory producing pesticides are clear, and some manufacturers also include postal codes, telephone numbers and telegraph registrations. Counterfeit and inferior pesticides cannot be clearly marked on the label.

6. See if there are two certificates and valid period for imported pesticides. If you have one, you can buy it with confidence.

7, look at the quality of the appearance. Mainly to check the pesticide for agglomeration, stratification, sedimentation and leakage. If there is one of these phenomena, it is an expired pesticide or an unqualified pesticide. It is best not to buy it.

8. See if the business unit is formal. When purchasing pesticides, be sure to check whether the operator has a business license and a pesticide business license. It is recommended that you go to the agricultural technology department with complete documents to purchase pesticides. They can also guide you when it is most appropriate to use the medicine.

X. Problems to be aware of when using pesticides

1. The right medicine, a variety of pesticides, different characteristics, should be targeted at the control object, select the most suitable pesticide.

2, timely medication, anti-effect is ideal.

3, strict control of the amount of application, should be used according to the recommended dosage, free to increase or decrease can easily cause crop damage or affect the effectiveness.

4, the application should be uniform, can not be re-sprayed or leaking spray to ensure the safety of crops, and the prevention and control of pests and diseases are effective.

5. Reasonable mixed pesticides can not increase the toxicity to humans and animals after mixing, and there is no chemical reaction between the active ingredients, which can not increase the cost of medication.

6, to safely apply drugs, dispense drugs, to prevent human and animal poisoning.

7. Highly toxic and highly toxic pesticides are prohibited from being used on fruits such as fruits, vegetables, fruit trees and Chinese herbal medicines.

X. Five alternative pesticides for banned pesticides in vegetable production

The “no pollution” of vegetable production is the trend of the times, and the majority of vegetable farmers have a deep understanding of this. However, five kinds of highly toxic and high-residue pesticides, such as methamidophos, which have been used by vegetable farmers for a long time, have been banned in the technical regulations for the production of pollution-free vegetables. Here, five alternative pesticides that ban pesticides are introduced to achieve the same control effect.

1, methamidophos. It is a broad-spectrum insecticide. It used to be used to kill all kinds of pests, but its high toxicity, residual period of more than 30 days, often causing poisoning incidents of humans and animals, is the primary banned pesticide in pollution-free vegetable production. Production should pay attention to:

(1) Lepidopteran pests such as Pieris rapae, Plutella xylostella, and pea pods. There are two types of alternative pesticides: one is biological pesticides, such as moth sorghum, century lore, peach xiaoling, agricultural land, etc.; the second is the use of compound pesticides, common compounding for dichlorvos

+BT, dichlorvos + kung fu, etc. Should pay attention to the use: 1 in the low-age spraying of pests, the effect is good; 2 rotation use of various insecticides, more use of biological pesticides, in order to avoid pests to produce resistance; 3 now pesticides have more contact, you should choose pests for food The best effect of spraying is that the bean pods crawl out of the pods for food at 6:00-8:00 in the morning, and the spraying effect is best.

(2) For the yellow scoop jumper, Huang Shougua and other migratory pests. Alternative pesticides include dichlorvos, agricultural land, and phoxim. Should pay attention to the use: 1 large area at the same time good control effect; 2 yellow scoop jumper a large number, in addition to spray control, should also use the root method to kill underground larvae; 3 interval 5-7 days, continuous control 2-3 times .

(3) Aphids and whitefly pests. It is easier to kill, and it can be controlled in time with the use of cockroaches, dichlorvos and other agents.

2, dicofol. Previously used to kill red spiders, mites and so on. The alternative pesticides are insects, worms, worms, etc., and the effect is obvious after use.

3. Omethoate. In the past, it was mainly used to kill cucurbits such as cucurbits.

4, carbofuran. Previously it was mainly applied to the soil to kill nematodes and other soil pests. Alternative pesticides include Miller and Dixon. In addition, the same effect can be achieved by using the method of turning the soil and applying lime.

5, methyl 1605. Previously used to kill a variety of vegetable pests, such as the tick moth, alternative pesticides and methods of use similar to methamidophos.

Vegetable production should strictly abide by pollution-free operating procedures, ban high-toxic, high-residue pesticides, and must strictly comply with the safety period for pesticides that are allowed to be used. By improving the level of pesticide application technology, it not only meets the requirements of pollution-free vegetables, but also achieves the goal of high yield and high quality.

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