New pesticides to control cotton bollworm

New insecticides developed in recent years, such as macrolide emamectin benzoate and spinosad, insect growth inhibitor hexaflumuron, chlorfluazuron, methoxyfenozide are has good control effect on cotton bollworm.

Bioassay results show that spinosad products have obvious ovicides effect on cotton bollworm; emamectin benzoate, spinosad, chlorpyrifos, lambda-cyhalothrin, phoxim, profenofos, efficient cypermethrin on eggs hatch has significant inhibited effect; emamectin benzoate, lambda-cyhalothrin, spinosad, chlorpyrifos, beta-cypermethrin, profenofos and phoxim have better poisoning effect on bollworm’s young, old larvae; insect growth regulator to the newly hatched larvae of cotton bollworm have obvious growth inhibitory effect. Field experiments showed that emamectin benzoate, lambda-cyhalothrin, profenofos, wherein the control effect of lambda-cyhalothrin is fast and efficient, the effect of spinosad and methoxyfenozide is slower, less effective.

Although chlorpyrifos’ toxicity is moderate, phoxim with less toxicity, and both were have good prevention and treatment effect on cotton bollworm’s larvae, but because of it belongs to high toxic pesticides to bees, fish, trichogramma, so that in field trials do not choose these two agents. Although lambda-cyhalothrin, beta-cypermethrin, profenofos be used for preventing and controlling cotton bollworm in the field for a longer time, but they still have good control effect; emamectin benzoate is a new macrolide compound, with efficient and ultra-efficient characteristics on certain pests and harmful mites, the main mode of action is stomach toxicity and tag out, its mechanism of action is to interfere with the pest neurophysiological activity, inhibitγ-amino butyric acid receptor chloride ion stream, blocking the movement neural information transmit, make the motor nerve palsyed, the insect stop feeding and death, has a strong osmosis on blade, kill pests under the epidermis, and have long duration. The test confirmed that after emamectin benzoate treating bollworm eggs, the effect on bollworm egg shell’s early larvae is the best, and both have good effect on bollworm’s young, old larvae, is an ideal bollworm control agents, this result is the same with other studies.

Spinosad is a microbial metabolite, belongs to low toxicity, broad-spectrum pesticides, biodegradable in the environment, do not pollute the environment, to lepidopteran pests have fast contact and stomach poison effect, with strong osmosis on blade, can kill pests under epidermis, longer duration, to some certain pests have ovicides effect. The study found that spinosad does have a toxic effect on bollworm eggs, and after treatment the newly hatched larvae’s mortality is high, but the effect of spinosad to young and old larvae is slower.

Methoxyfenozide is a low toxicity, dihydrazide insect growth regulator, belonging the molting hormone analogues, able to simulate the function of Lepidoptera larvae molting hormone, to promote it molting, mature early, incomplete development, this pesticide have little effect on other insects except Lepidoptera, with a long duration, stable, low toxicity, efficient, safe for people and livestock and other features, it is the ideal selective insecticides in comprehensive prevention and control. The results show that although methoxyfenozide to the newly hatched larvae of cotton bollworm have significantly inhibited effect, but the effect is slow, and its field trials were less effective.

Source:http://www.cospcn.com