Toxicity Mensurationes and Efficacy Trials of Several Insecticides Against Cotton Aphid Aphis gossypii(Glover)

resistances of A.gossypii to chemical have developed very fast,and the resistance machenisms are complicated. In 2005,a research program titled with The application of high-effect and safety for replacing the hypertoxic insecticides was set up by the Chinese Ministry of Agriculture,this program will be one of the technical guarantees to realize the decision target that the production and use of five major hypertoxic organic phosphorous such as methamidophos must be all-round prohibited in China.The effects of 13 belong to different types against cotton aphid A.gossypii including seedling aphid and summer-type aphid were tested in laboratory and field.The toxicities of these to seedling aphid and summer-type aphid were tested using leaf dipping method in laboratory.The cotton aphids were collected from cotton field in Langfang County,Hebei Province,in June and August 2005 separately.The alate and neonatal aphids were eliminated.The symmetrical and consistent A.gossypii were selected to test.Based on the results got from indoor bioassays,six were selected to measure the field efficacy to A.gossypii.The field trials were tested during the seedling aphids and summer-type aphids outbreak periods in Langfang cotton field.The results of indoor bioassays showed that the populations of seedling aphid and summer-type aphid were desirably kept under control by acetaniprid,imidacloprid,avermectin,carbosulfan,phoxim and chlorpyrifos.The similar results were got in the field when these six were used by spraying.Nicotine pesticide-acetaniprid and imidacloprid,antibiotics pesticide-avermectin,carbamate pesticide carbosulfan,these new type insecticides,have low toxicities to fishes,bees and natural enemies and are safe to environment,but phoxim and chlorpyrifos have strong toxicity to fishes,bees and natural enemies.As a whole,among the 13 tested insecticides,acetaniprid,imidacloprid,avermectin and carbosulfan were selected to be the effective to control A.gossypii.