Popularization of high-efficiency low-toxic pesticide knowledge

Pesticides are now indispensable in agriculture. In people's perception, pesticides with good effects are relatively toxic, pesticides with low toxicity have poor effects. So are there high-efficiency low-toxic pesticides?

High efficacy, generally means that under normal conditions, pesticides achieve the following control effects: pesticides apply 50 grams of active ingredients per mu of field, the control effect is greater than 90%; fungicides spray 100 grams of active ingredients per mu of field, which The control effect is greater than 70%; the herbicide applies 250 grams of active ingredient per mu of field, the control effect is greater than 70%. For example, fenvalerate is used in the period of pests to prevent control small green leafhoppers in tea, the effective ingredient is 1.5-2.5 grams per mu; cypermethrin is used in the 2-3 instars of larvae, the effective ingredient is 0.25- 0.5 grams; cypermethrin is taken out for 3-6 days in the citrus new shoots, when the length is less than 0.5 cm, it is used for egg hatching larval 1-2 instars, the active ingredient is 0.8-1 grams per mu; It is used in the period to prevent treat soybean heartworms. 1-1.5 grams of effective ingredients are used per mu, the control effect is very good. Fuji No. 2 Tricyclazole prevent Chaga blast, Yekuning against water white leaf disease, Puccinia Ning against wheat stripe rust, Chlorothalonil to prevent flower rust leaf spot, Carbendazim to control vegetable powdery mildew, Sclerotinia anthracnose, etc., the effective ingredients per mu need exceed 100 grams. Take catch net to annual grass weeds at 2-4 leaf stage. The perennial grass weeds are used in the 3-5 leaf stage, simazine controls dry land weeds, field weeds, garden weeds. The effective ingredients per mu are within 250 grams.

The above-mentioned chemicals have reached the high-efficiency standards for the above-mentioned diseases, insects weeds, they are all highly effective pesticides. Pesticides are mostly toxic to higher animals. The magnitude of toxicity is often expressed in the lethal dose (LD50) the lethal concentration (LC50) in rats, mice rabbits, the unit is mg / kg body weight. The smaller the value of LD50 ( LC50), the greater the toxicity; conversely, the larger the value, the smaller the toxicity. The toxicity of pesticides to mice rabbits can also reflect the magnitude of toxicity to humans animals. The acute toxicity lethal dose (LD50) mg / kg of low-toxic pesticides is: oral administration of rats over 500-5000; rabbit skin application over 350-2810; inhalation of rats through the respiratory tract for 4 hours to kill 1 / 3-1 / 2 concentration ( LC1 / 3-1 / 2) PPM, above 1000-10000.

According to this standard, pesticides with low toxicity are: phoxim, methamidophos, Nong Meng Te, Ke Mite, mite treatment, Tolk, Rebis, Fuji No. 1, Fenpyrin, Chlorothalonil , Carbendazim, carbendazim, chlordiazepine, manganese zinc, DT emulsion, Hedazhuang, Nongde, Wei Luosheng, Youke barnyardgrass, butachlor, chlorfenapyr, chlorpyrifos Bendaxon, Dur, Lasso, Fluvoxine, Jingwensha, Nahuojing, Hetrazine, etc. Among the above pesticides, the first six are insecticides acaricides, the middle eight are fungicides, the rest are herbicides.