Susceptibility status of Aedes aegypti (L.) and Aedes albopictus Skuse larvae obtained from 12 states in Malaysia were evaluated against five insect growth regulators (IGRs), namely, pyriproxyfen, methoprene, diflubenzuron, cyromazine, and novaluron under laboratory conditions. Field populations of Ae. aegypti exhibited moderate resistance toward methoprene and low resistance toward pyriproxyfen, with resistance ratios of 12.7 and 1.4, respectively, but susceptibility to diflubenzuron, cyromazine, and novaluron. On the other hand, field populations of Ae. albopictus exhibited low resistance against diflubenzuron and novaluron, with resistance ratio of 2.1 and 1.0, respectively, but susceptibility to other tested IGRs. Our study concluded that the tested IGRs provide promising results and can be used to control field population of Ae. aegypti and Ae. albopictus, especially cyromazine. The use of IGR should be considered as an alternative when larvae develop resistance to conventional insecticides.

Background: There are several species of mosquitoes that readily attack people, and some are capable of transmitting microbial organisms that cause human diseases including dengue, malaria, and Japanese encephalitis. The mosquitoes of major concern in Malaysia belong to the genera Culex, Aedes, and Armigeres. Objective: To study the host-seeking behavior of four Malaysian mosquitoes commonly found in urban residential areas in Kuala Lumpur. Methods: The host-seeking behavior of Aedes albopictus, Armigeres kesseli, Culex quinquefasciatus, andCulex vishnui was conducted in four urban residential areas in Fletcher Road, Kampung Baru, Taman Melati, and University of Malaya student hostel. The mosquito biting frequency was determined by using a bare leg catch (BLC) technique throughout the day (24 hours). The study was triplicated for each site.