Laboratory Evaluation of Some Local Components as Attractants to the Mosquito, Culex pipiens Females

Culex pipiens is a cosmopolitan mosquito species and is an important vector for periodic lymphatic filariasis, West Nile virus, and Rift Valley fever.  Using newer technologies like the application of semiochemical-baited traps for mass trapping or killing of adult females of mosquito under integrated pest management (IPM) programs have been encouraged instead of intensive using of chemical insecticides to avoid hazardous effects to human, animals, and livestock in addition to environmental problems. The present study focused on the evaluation of the efficacy of attractive traps in trapping the mosquito, Culex pipiens females under laboratory conditions. The traps were supplied with some of safe components such as (1) sucrose, molasses and CAPL* (Central Agricultural Pesticides Laboratory) alone and mixed with Baker’s yeast granules that cause releasing of CO2 as an attractive material and (2) ammonium hydroxide (33%) and lactic acid alone and mixed with molasses or sucrose. The obtained results showed that the sugary solutions (sucrose, molasses, and CAPL* solutions) alone had lower attractive effect (46.7- 72.0% attraction after two days exposure) as compared with those that were mixed with Baker’s yeast granules (92-100% attraction). In addition CO2 emanation showed attraction and killing effects on tested mosquitoes. Ammonium hydroxide (33%) exhibited high attraction effect at low dilution (1 µl/100 ml water attracted 100% of mosquitoes after two days exposure) while lactic acid was weak attractant (1 µl/100 ml water attracted only 44% of mosquitoes). So lactic acid (5 µl/100 ml water) attraction (60% after two days) was augmented by adding of 50 gm molasses and 50 gm sucrose (96% and 92% attraction, respectively at day 2 post-exposure). It can be concluded that solutions showed ≥ 90% attraction after two days exposure (sucrose + yeast, molasses + yeast, CAPL* + yeast, ammonium hydroxide (33%) at 1 µl and lactic acid at 5 µl mixed with sucrose or molasses) are considered attractive materials, but for control purposes, solutions which cause complete death for the attracted mosquitoes are preferred such as sucrose + yeast, molasses + yeast, and CAPL* + yeast. However, further intensive studies are needed to test the efficacy of such materials as control agents under field conditions.