What are the main characteristics of organophosphate insecticides?
(1) Relatively broad insecticidal spectrum. The organophosphate insecticides commonly used today can control many agricultural and forestry pests, and some can be used to control public health pests and external parasites of livestock and poultry. (2) Diversified modes of action, able to meet many different needs. Most varieties have contact and stomach poison action, and some varieties...
(1) Relatively broad insecticidal spectrum.
The organophosphate insecticide varieties commonly used today can control many agricultural and forestry pests, and some can be used to control public health pests and external parasites of livestock and poultry.
(2) Diversified modes of action, able to meet many different needs.
Most varieties have contact and stomach poison action, some have systemic or penetrating action, and a few have fumigant action, so they can be applied in many ways to control different types of agricultural and forestry pests, including above-ground, underground, boring, and piercing-sucking pests. Their insecticidal mechanism is to inhibit the activity of cholinesterase in the pest's body, disrupting normal nerve conduction and causing a series of nervous system poisoning symptoms until death.
(3) Relatively high toxicity, so safety should be noted during use.
Most varieties are relatively highly toxic to humans and livestock, and some are extremely toxic, such as phorate, methamidophos, demeton, etc. During use, attention should be paid to health and safety, and a certain pre-harvest interval should be ensured before harvesting agricultural products to avoid poisoning from pesticide residues.
(5) Easy to detoxify.
Although organophosphate insecticides are relatively highly toxic and can easily cause poisoning in humans and livestock, highly effective antidotes such as atropine and pralidoxime are already widely used.
(4) In the environment, they degrade easily.
General varieties readily degrade into non-toxic substances in plants and animals, and under natural conditions such as sunlight, wind and rain, they readily hydrolyze and oxidize. Therefore, they should be stored away from light and moisture.
(6) Resistance develops relatively slowly, and they are relatively safe for crops.
Although organophosphate insecticides have been used for a very long time and their efficacy has declined somewhat compared with the beginning, pest resistance to them has developed relatively slowly, and they are still used in large quantities today. At the same time, they are generally relatively safe for crops and not prone to causing phytotoxicity, though of course some crops are more sensitive to certain varieties, such as the phytotoxicity of trichlorfon to sorghum, and the certain phytotoxicity of dichlorvos and omethoate to corn and peach trees at high concentrations.
(7) The vast majority of organophosphate insecticides readily decompose under alkaline conditions, so they must not be mixed with alkaline substances.
At present, the organophosphate insecticide varieties registered and widely used in China mainly include: parathion, methyl parathion, methamidophos, acephate, isocarbophos, dimethoate, omethoate, dichlorvos, malathion, phoxim, monocrotophos, phorate, chlorpyrifos, triazophos, isofenphos-methyl, trichlorfon, methidathion, profenofos, etc.