Resistant Pest Management Newsletter

As with other insects, resistance to insecticides has become a limiting factor in the use of insecticides to control mosquitoes. Mosquito control depended on the use of insecticides for a long time (initially organochlorines, followed by organophosphates, carbamates and pyrethroids). This study aimed to determine the susceptibility of Anopheles arabiensis adult to the public health and agricultural insecticides, viz. DDT 4%, fenitrothion 1%, malathion 5%, bendiocarb 0.1%, propoxur 0.1%, deltamethrin 0.05% and lambdacyhalothrin 0.05% at El Rahad Agricultural Corporation (RAC) area, Central Sudan, to provide base-line data about the Anopheles susceptibility, by determining their KDT50 and KDT95. The WHO procedure was adopted. The number of knockdown (Kd) mosquitoes were recorded after 10, 15, 20, 30, 40, 50 and 60 min. of exposure. The percent mortalities after 24 hrs for each chemical were determined. The KDT50 and KDT95 were calculated with the 95% CL. These were as follows: for DDT 4% (34.84 and 74.41), in fenitrothion 1% (58.96 and 112.44), in malathion 5% (49.37 and 141.25), in bendiocarb 0.1% (97.20 and 292.06), in propoxur 0.1% (38.88 and 138.20), in deltamethrin 0.05% (58.30 and 147.82) and in lambda-cyhalothrin 0.05% (34.80 and 66.65) respectively. Some recommendations were listed: 1-The importance of annual monitoring and evaluation of insecticides commonly used in the area to evaluate the status of resistance. 2-Conducting bioassays for insecticides recommended but not commonly used. 3Conducting bioassays for insecticides commonly used for other purposes and possibility for mosquitoes to come in contact with them. 4Screening for new molecules with new modes of action.