Introduction to the characteristics of benzoylurea insecticides

Benzoylurea insecticides are called insect growth regulators, and their insecticidal characteristics can be summarized as follows. (1) the insecticidal mechanism is special. After entering the insect body, this kind of insecticide inhibits the synthesis of the epidermis of the larvae, making it impossible for the insect to grow new skin, resulting in the insect being unable to molt and die. Thus it can be seen that benzoylurea insecticides only act on insects with molting habits. It has no effect on adults that do not shed their skin. However, it can cause indirect effects, such as infertility, reduction of fecundity and decrease of egg hatching rate. (2) strong selectivity. It is only effective for molting insects and is safe for most natural enemies insects, fish, shrimp and other aquatic organisms, bees and so on. (3) low toxicity and low residue, chitin is a unique epidermal substance of insects, but not in other animals, so it has low toxicity to humans and animals, no chronic toxicity, easy to decompose in animals and plants, and low residues in agricultural products. Little pollution to the environment. (4) most varieties are not easy to develop resistance, and there is no cross-resistance to other kinds of insecticides, but some varieties develop resistance soon after continuous use, such as Dingchonglong against some Lepidoptera pests. (5) the insecticidal effect is slow, and this kind of insecticide only plays a role in the molting process of insects, and it usually takes at least 3 days to die, so it is necessary to apply insecticides early in the low instar stage of larvae, and when pests occur seriously, should also be used in combination with quick-acting pesticides. (6) because the silkworm is a molting insect, this kind of insecticide is highly toxic to silkworm, so it should be used cautiously in and around the silkworm area. At present, the main varieties used are: diflubenzuron, flufenuron, buprofezin, etc.