What are the commonly used pesticides? Understanding the effects of various pesticides in one article
Pesticide, the currently unified English name in the world is pesticide——that is, “killing agent”, but in fact so-called pesticides refer to chemicals and biological agents used to control harmful organisms that endanger agricultural, forestry and animal husbandry production (pests, pest mites, nematodes, pathogenic bacteria, weeds and rodents. Later, through a relatively long process of production and life development, people gradually realized that some natural substances have the ability to control harmful organisms in agriculture and animal husbandry. By category 17, etc.) and to regulate plant growth. Usually various adjuvants used for hygiene and to improve the physicochemical properties of active ingredients are also included.
Insecticides
Emamectin benzoate
Compared with abamectin, its insecticidal, acaricidal and nematicidal activity is increased by 10-100 times, and its insecticidal spectrum is broadened; it acts mainly by stomach poison and also by contact action; pests undergo irreversible paralysis and stop feeding, and die only after 2-4 days, so its insecticidal speed is relatively slow; its residual activity is long, 10-15 days for pests and 15-25 days for mites. It has no systemic activity in crops, but can penetrate epidermal tissue; it has extremely high activity against Lepidoptera pests, mites, Coleoptera and Homoptera pests, and thrips, and is not likely to cause pests to develop resistance; it degrades easily in soil; it is highly safe for all crops under protected cultivation or at 10 times the recommended dose; after more than 10 days, a second insecticidal peak appears;
Imidacloprid
Neonicotinoid; contact, stomach poison and systemic; pests die from paralysis; good quick-acting performance, with relatively high control efficacy within 1 day, and a residual period of up to about 25 days; higher temperatures give better insecticidal effects; pests with piercing-sucking mouthparts; easily absorbed by crops and distributed upward, with root uptake action;
Tebufenozide
Promotes molting of Lepidoptera larvae; its mechanism of action is opposite to that of other larval molting inhibitors; effective against both older and younger larvae; feeding stops within 6-8 hours (stomach poison action), faster than molting inhibitors, and death begins after 3-4 days; no phytotoxicity, safe for crops, and no residual spray marks;
Malathion
At low temperatures its toxicity decreases, so the application rate or concentration can be appropriately increased; pests with chewing mouthparts and piercing-sucking mouthparts; contact and stomach poison action, with a certain fumigant and penetrating effect; strong knockdown power against pests, with good effects at high temperatures; short residual life; prone to phytotoxicity on some varieties such as sorghum, melons and beans, pears, grapes and cherries, so it should be used with caution; stop use 10 days before fruit harvest. Diflubenzuron
Apply at the early larval stage; the older the larvae, the poorer the control effect.; inhibits chitin synthesis; stomach poison action, can penetrate the cuticle of insects and eggs to act, but has no systemic action; spray on the underside of plant leaves; the efficacy period lasts more than 30 days and is resistant to rain erosion; safe to natural enemies, highly active against Lepidoptera and mosquito and fly larvae; death begins 3 days after application and peaks at 5 days; ineffective against adults;
Quinalphos
Insecticidal and acaricidal action, with stomach poison and contact action, no systemic or fumigant properties; good permeability, certain ovicidal action, fast degradation on plants, short residual life; good effect in controlling chewing and sucking pests. Acetamiprid, chloronicotinyl pyridine class; contact and stomach poison, very good systemic activity; inhibits the activity of acetylcholine receptors; effectively controls aphids, leafhoppers, whiteflies, scale insects in Hemiptera and leafminers, small borers in Lepidoptera, as well as longhorn beetles, thrips and other pests in Coleoptera; granule formulations used as soil treatment can control underground pests; quick-acting, with a long residual period of up to about 20 days;
Buprofezin
Inhibits chitin synthesis and interferes with metabolism; takes effect only 3—7 days after application, has no direct killing power against adults, but can shorten their lifespan, reduce egg production, and most of the eggs laid are infertile, and even if larvae hatch they soon die. It has good control effects on Hemiptera pests such as planthoppers, leafhoppers, whiteflies and scale insects, with an efficacy period of more than 30 days; it must not be used by the toxic soil method; it should not directly contact Chinese cabbage or radish, otherwise phytotoxicity such as brown spots and leaf greening will occur.
Isoprocarb
Contact action, with certain penetrating and translaminar activity, and strong quick-acting performance; mainly used on rice to control rice planthoppers and leafhoppers, and can also control thrips; must not be used at the same time as propanil, and an interval of more than 10 days is required; this agent is phytotoxic to taro and must not be used.
Phoxim
Broad insecticidal spectrum, strong knockdown power, mainly contact and stomach poison action, no systemic action, very effective against Lepidoptera larvae, and also has a certain killing effect on eggs; unstable to light, best used at night or in the evening, with a short residual period; in soil, its residual period is very long, suitable for controlling underground pests; cucumber and kidney bean are sensitive to phoxim and prone to phytotoxicity, sorghum is sensitive and should not be sprayed; in corn fields only granules can be used to control Asian corn borer, and do not spray to control aphids, armyworms, etc.
Methidathion
Contact, stomach poison and penetrating action; pests with chewing and piercing-sucking mouthparts, with special efficacy against scale insects, and a certain controlling effect on mites; residual life 10-20 days; the concentration in orchards must not be too high, otherwise brown lesions will be caused;
Bifenthrin
Insecticide and acaricide; stomach poison and contact action; rapid action, long residual life; activity several times higher than other pyrethroid agents; stop use 4 days before vegetable harvest; can exert better efficacy at low temperatures, use in spring and autumn. Methomyl acts rapidly; contact and stomach poison action, and is also
Phoxim
Contact and stomach poison action, no systemic action; fast knockdown speed, can control underground pests and larvae of Lepidoptera pests; easily decomposes in light; cucurbits, beans, sugar beet and corn are sensitive to phoxim; stop use 5 days before harvest. Chlorpyrifos (Lorsban, chlorpyrifos, Dursban) broad-spectrum, stomach poison, contact and fumigant; good effect on underground pests; Coleoptera, Lepidoptera pests and pest mites; cucurbits are sensitive at the seedling stage;
Cypermethrin
Contact and stomach poison action, as well as repellent action, strong knockdown power, fast insecticidal speed; special efficacy against Lepidoptera pests, and also effective against aphids and small green leafhoppers. Poor control effect on mites and mirids; relatively long residual period; relatively weak penetrating power, less contamination inside fruits;
Deltamethrin
Contact action, also with stomach poison, repellent and antifeedant action; special efficacy against Lepidoptera larvae, ineffective against mites; very weak penetrability, only contaminates the fruit skin;
Cyhalothrin (Kung Fu, PP321)
Strong contact and stomach poison action against pests and mites, and also repellent action; resistant to rain erosion; must not be used for soil treatment;
Cyfluthrin (Baythroid, Baythroid)
Contact and stomach poison; very good effect on various Lepidoptera larvae; ovicidal; repellent action;
Bacillus thuringiensis
Bacterial; stomach poison, produces bacterial toxins; relatively slow efficacy; residual period about 10 days; the higher the temperature, the more feeding, the better the effect; larvae of Lepidoptera pests such as imported cabbageworm, diamondback moth, tobacco cutworm, beet armyworm and silver Y moth; it can exert insecticidal action only above 30℃; use broad-spectrum antibiotic insecticides and acaricides 2-3 days in advance; stomach poison and contact action, repellent;
Metaldehyde
Very strong attractant power; spring and autumn rainy seasons; after sowing or transplanting seedlings; at low temperatures (below 1.5℃) or high temperatures (above 35℃), because snail activity is weak, the control effect is affected;
Diafenthiuron
Thiourea insecticide and acaricide; used on cotton, fruit trees, vegetables and tea trees; has systemic and fumigant action, and under ultraviolet light transforms into substances with insecticidal activity, so it is suitable for use on sunny days; resistant aphids, large leafhoppers and tobacco whiteflies, etc.; controls damage by diamondback moth, cabbage butterfly and noctuid moths;
Diflubenzuron
Chitin synthase is inhibited; causes adult sterility, and has toxic killing effects on larvae, pupae, adults and eggs; the control effect is more significant against larvae of Lepidoptera and Diptera.
Hexaflumuron
Insecticidal and ovicidal activity, and quick-acting, especially in controlling cotton bollworm; various Coleoptera, Diptera and Homoptera insects, inhibiting pest feeding speed; relatively fast knockdown power
Acaricides
Pyridaben
Broad-spectrum, high-efficiency, contact action; eggs, nymphs and adult mites; quick-acting and long residual life; both upper and lower leaf surfaces should be sprayed evenly
Propargite
Contact and stomach poison; poor effect on eggs; good effect when used above 20℃, and below 20℃ the effect decreases as temperature falls; residual life can reach 15-25 days; when used under high temperature and high humidity conditions, a low concentration must be used.
Clofentezine
Spraying before winter eggs hatch can control phytophagous spider mites throughout the season; special efficacy against European red mite (apple red spider mite), no effect on predatory mites and beneficial insects; organic nitrogen heterocyclic class; contact action, kills eggs and also young and nymph mites, but has relatively poor effect on adult mites. Residual life can reach 50—60 days; to control apple red spider mite, apply at the initial hatching stage of overwintering eggs before flowering, and to control hawthorn red spider mite, apply at the peak egg-laying stage of overwintering adults after petal fall; efficacy is relatively slow, and the highest acaricidal activity is reached only 2—3 weeks after application; applying at the appropriate time during the initial mite hatching stage is not affected by high or low temperature, and it can be mixed with lime sulfur; during storage, prevent freezing and direct sunlight;
Hexythiazox
Has penetration through the plant epidermis, with no systemic translocation action. Has strong ovicidal and nymphicidal properties, ineffective against adult mites, but has an effect of inhibiting hatching; a non-temperature-sensitive acaricide, its efficacy can last about 50 days, and its efficacy develops relatively slowly, so application should follow the principle of being appropriately early; can be mixed with various pesticides such as Bordeaux mixture and lime sulfur. Good control effect on spider mites, poor control effect on rust mites and gall mites;
Azocyclotin
Strong contact action; broad-spectrum, can kill nymph mites, adult mites and summer eggs, but is ineffective against winter eggs. Stable to light, long residual life, safe for crops; spraying on sweet orange above 32℃ can cause phytotoxicity to new shoot tender leaves, so avoid use in high-temperature seasons.
Fenpropathrin
A nerve poison with certain acaricidal activity but no fluorine; relatively long residual life; repels feeding and egg-laying, non-temperature-sensitive; Lepidoptera; not used as a dedicated acaricide; residual life about 10 days.