Residents in irrigated urban agricultural sites face numerous mosquito problems such as increased mosquito populations and reduced insecticides susceptibility due to the creation of mosquito breeding sites and agricultural use of insecticides and hence require effective protective products against them. In this study, the protection effectiveness of three pyrethroid formulated mosquito coils of Malaysian origin against Anopheles gambiae sensu lato from an irrigated urban agricultural site in Ghana were evaluated for their potential use. Sucrose fed An. gambiae s.l. were exposed to insecticide-containing coils in a 70 cm x 70 cm x 70 cm glass chamber to assess the insecticidal effect of the coils. The 0.005% metofluthrin coil caused the most rapid knockdown of 50% of the test mosquitoes. The mean lethal effect of the coils on An. gambiae s.l. were as follows; 0.005% metofluthrin (86%), 0.3% d-allethrin (74.33%), 0.15% d-trans allethrin (72%) and the 0.25% d-allethrin reference coil (69%). The 0.005% metofluthrin coil achieved the highest insecticidal effect on An. gambiae s.l. compared to the other coils and hence performed better than the others as an anti-mosquito product. All the three test coils were effective against An. gambaie s.l. from the irrigated agricultural site compared to the reference coil.
Plants contain bioactive compounds and are constantly explored as safer alternatives to conventional insecticides. Despite numerous studies on many plants, information on the insecticidal potential of underutilised plants like tiger nut, Cyperus esculentus L., are scant, although their pharmacological potentials are well known. Hence, this study investigated the larvicidal potential of crude aqueous extracts of two C. esculentus varieties (black and yellow) on the mosquitoes Aedes aegypti (L.) and Culex quinquefasciatus (Say). Mosquito larvae were exposed to C. esculentus crude extracts using the larval bioassay technique of the World Health Organization. Differential larvicidal responses were observed in the test mosquitoes and extracts of Black Dried Tiger nuts (BDT) were more larvicidal than Yellow Dried Tiger nuts (YDT). Acute larval toxicity of the extracts was more pronounced on Cx. quinquefasciatus than Ae. aegypti. The results indicate the potential of C. esculentus (particularly BDT) as a source of mosquito bioinsecticide and merits further studies as a safer alternative to conventional insecticide-based vector control.
The medically important mosquito, Aedes albopictus is native to Asia and has become a major health concern in most Asian countries including Malaysia. Being recognized as a dengue vector, a clearer understanding of how mosquito populations are geographically connected, may therefore represent a profound yet significant understanding of control strategies. There are no documented reports on the genetic structure of Ae. albopictus populations from different developed settlements inferred from microsatellite DNA markers in Malaysia, particularly in Penang Island (Northern Peninsular Malaysia). Here, we assessed the molecular population genetics of Ae. albopictus in terms of their allelic variation, genetic diversity and population structure. A total of 42 mosquitoes were sampled from Jelutong, Batu Maung and Balik Pulau which represented urban, suburban and rural areas in Penang Island respectively and analysed for polymorphism at six microsatellite loci. All of the microsatellite markers were successfully amplified and were polymorphic, showing low genetic structure among geographic populations (FST= 0.0362). It is supported with admixture individuals observed in STRUCTURE and FCA and this suggests that high gene flow has been experienced between populations. These findings implicate passive dispersal through human-aided transportation; as a factor shaping the genetic structure of Ae. albopictus populations in Penang Island.