1. According to its composition and source

Inorganic pesticides, such as lead arsenate, calcium arsenate, arsenite, sodium fluoride, sodium fluorosilicate, sulfur, zinc phosphide, etc.

Organic pesticides. Natural organic pesticides can be divided into plant pesticides (such as roe, pyrethrum, tobacco, pine resin, anisin, neem, etc.) and mineral pesticides (such as diesel emulsion, petroleum emulsion, etc.). Synthetic organic insecticides include organochlorine insecticides, organophosphorus insecticides, organic nitrogen insecticides, and pyrethroid insecticides.

Microbial insecticides, such as Bacillus thuringiensis, yellow ground tiger granular virus, cotton bollworm granular virus, Pieris rapae granular virus, Plutella xylostella granular virus, Beauveria bassiana, Metarhizium anisopliae, Gibberella spp.

2. According to its function or effect

Stomach poison is a medicine that is ingested by the pest’s mouthparts into plant tissue or poisonous bait with a medicament, and is absorbed by the pest’s digestive system to cause the pest to be poisoned to death. Such as acephate, trichlorfon and so on.

Contact insecticide: After the insects come into contact with the agent, the agent enters the insect body from the epidermis, feet, antennae, air valve and other parts, causing the insect to be poisoned to death. Such as malathion and other organic phosphorus insecticides, pyrethroid insecticides and so on.

Fumigant. The medicament can volatilize into toxic gas at normal temperature, or produce toxic gas through a certain chemical action, and enter the body through the respiratory system such as the valve of the pest, causing the pest to be poisoned to death. Such as methyl bromide, phosphine and so on.

Systemic agent, which can be absorbed by the roots, stems, leaves and other tissues of plants and transmitted to other parts of the tips, or absorbed by seeds and transmitted to various parts of the seedlings and even plants. The amount of the drug is sufficient to poison the harmful insects. A lethal potion. Such as phorate, methyl isothion, methyl thiocyclophos and so on.

Repellent. The medicament itself is non-toxic to kill pests, but its special smell makes pests repellent, thereby achieving the purpose of protecting crops from harm. Such as mothballs.

Antifeedant. Pesticides can destroy the normal physiological functions of the pests and the secretion of digestive enzymes in the digestive tract, and interfere with the pest’s nervous system after being contacted or fed by the pests. Immortal insects also undergo physiological atrophy and metamorphosis. Such as insecticide, a variety of terpenoids (such as azadirachtin) and so on.

Attractants are agents that can attract various pests and then kill them. Most commonly used is a sex attractant released by female insects that can attract males of the same species for mating in a very small amount. When this kind of sex attractant reaches a certain level in the air, it will make pests fascinated, reduce mating, spawning and reproduction, thereby reducing the harm of pests. Such as cotton bollworm sex attractant, red bollworm sex attractant, big borer sex attractant, diamondback moth sex attractant and so on.

Sterility agent. When insects contact or ingest this agent, they destroy the function of their reproductive organs and make them lose their reproductive ability, causing female insects to mate and not lay eggs, or the eggs that lay cannot hatch normally, even if they hatch their offspring, they can’t normally hatch. Reproduction and reproduction reduce the number of populations and even become extinct within a certain range. Such as tepa, thiotepa and so on.

Specific insect growth regulator. Such agents mainly interfere with and destroy the normal metabolism of pests, inhibit the synthesis of chitin, and cause malformation or death of larvae.

At present, many synthetic organic pesticides have several insecticidal effects at the same time. For example, most organophosphorus pesticides have both stomach toxicity and contact effect; most pyrethroid insecticides have both stomach toxicity and contact effect, but also have a certain repellent effect. These insecticides with multiple insecticidal effects can be called comprehensive insecticides.

3. According to its toxicity

Very toxic and highly toxic agents. Such as parathion, methyl parathion, phosphoramine, methamidophos, hydrocarbophos and so on.

Low- and medium-toxic agents. Such as acephate, triazophos, profenofos, fenfluphos, fenthion, quinalphos, pyridazinphos, chlorfenaphos, fenvalerate, cis-fenvalerate, bromide Pyrethrin, Cypermethrin, Cis-cypermethrin, Lambda-cyfluthrin, Cyfluthrin, Lambda-cyfluthrin, Bifenthrin, Cypermethrin, Flufenuron, Buprofezin, Bacillus thuringiensis, Beauveria bassiana, Tobacco , Fenixin and so on.

4. Precautions for purchase

Like other products, insecticide products have many problems, and consumers should pay attention to them when buying. In addition, pesticides are a special product, which involves a lot of knowledge and technology, and consumers should be more careful when buying them.

Do not purchase insecticides that do not indicate effective insecticidal ingredients.

Among chemical pesticides, it is recognized that pyrethroid insecticides are relatively safe, while organochlorine, organophosphorus and carbamates are less safe than the former. Among the many pyrethroid insecticides, the safety is also different. Generally, permethrin, tetramethrin, allethrin and deltamethrin are safer.

Do not buy insecticide products that are processed and produced by insecticides that have been banned.

When aerosol pesticides and other products leave the factory, they must strictly implement the "three certificates" system that indicates the production permit number, pesticide registration number and product quality standard number. Otherwise, they are illegal products and cannot be purchased.

The foreign insecticide products that enter the Chinese market should also be carefully distinguished, not blindly credulous.

5. Precautions for use

Use pesticides as sparingly as possible, but try not to use them when not in use. Minimize the contact with pesticides. If you don't stay in the room where the pesticides are applied, you should leave immediately after applying the pesticides. After an hour and a half, you can open the doors and windows to fully ventilate and exhaust before entering.

Do not allow infants and children whose brain development is not perfect to come into contact with pesticides, so as to avoid adverse effects on children's brain development.

When using insecticides in the kitchen, be careful not to contaminate food, kitchen utensils, etc.

After applying insecticides and insecticide creams, bathe and change clothes.

To use pesticides to prevent and control crop pests, in order to achieve the best insecticidal effect, in addition to selecting the right counterparts and applying them in a suitable period, special attention should be paid to the time and location of the application.

1. According to climatic characteristics and the day and night activities of pests, choose to apply pesticides at a favorable time.

The appropriate time for pesticide application is from 9 to 10 in the morning and after 4 in the afternoon. Because after 9 o'clock in the morning, the dew on the crop leaves has dried up, and it is also the time when the sunrise pest activity is at its peak.

Applying pesticides at this time will not affect the control effect due to the dew diluting the liquid, but also make the pests and pesticides directly contact, increasing the chance of pest poisoning.

After 4 p.m., the sun is westward, the light is weakened, and the temperature is lowered, and it is just when flying activities and nocturnal pests are about to be dispatched at dusk. Applying pesticides at this time can apply the pesticides to the crops in advance.

When the pests come out to move or eat at dusk and night, they will be exposed to venom or poisoned by feeding. At the same time, it can also avoid the evaporation loss of the liquid medicine and the failure of photolysis.

2. According to the harmful parts of the pests, choose different medicines and adopt different application methods to deliver the medicines in place.

For pests that endanger the roots, spray the pesticide on the roots or in the sowing ditch; for pests that feed on the underside of the leaf, spray the liquid on the opposite side of the leaf.

To control red bollworms and cotton bollworms, spray the medicine on the flower buds, green bells and the tips of the clusters; to prevent stem borers and to sprinkle poisonous soil on the seedlings; to control white ears, spray or splash water.

To prevent rice planthoppers and rice leafhoppers, spray the liquid medicine on the base of the rice plant; to control Spodoptera litura, spray the liquid medicine on the flower buds and young pods.

In addition, for concealed pests such as cotton aphid, red spider, rice planthopper, rice leafhopper, etc., according to their piercing and sucking mouthparts feeding method, other parts of the plant that are passed on to the plant after absorption by a strong systemic insecticide can be selected , To achieve the purpose of delivering medicines in place.

Only by applying pesticides for insects and delivering the pesticides in place can they hit the key points and achieve the effect of pesticides to pest control, so that the drugs can play the best role and obtain the ideal insecticidal effect.

Why are pesticides less effective the more you use them

A kind of medicine has a good insecticidal effect when it is first used, but with the continuous increase of the dosage and the continuous expansion of the scope of use, cases of increasing resistance to the drug continue to appear.

The most prominent is cis-fenvalerate, which is often said in the 1980s advertisements as "justice", and justice will soon be unable to be done, because even if the dose is increased by dozens of times or even hundreds of times. Or the concentration of the medicine cannot kill the pests.

This is actually because pests are resistant to pesticides, which is the ability to tolerate the amount of drugs that kill most individuals in a normal population and develop in their populations.

In fact, there are individuals with different susceptibility to pesticides in the natural pest population. The process of using insecticides is actually a process by which insecticides have a selective effect on insect populations.

Every time a pesticide is used, relatively resistant individuals will be left, and relatively sensitive individuals will be killed, and the resistance level of the pest population will be more or less increased.