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The Aedes mosquitoes are important vectors of Zika, chikungunya, yellow fever, and Ross River arboviral diseases. The challenges caused by the over-reliance on chemical insecticides in managing the vectors and as well the diseases they transmit have led to increased emphasis on developing more effective and environmentally friendly alternatives. This study investigated the phytochemicals present in Allium sativum and Cymbopogon citratus mixed together in a ratio of 1:1 and the larvicidal efficacy of their synergistic combination against Aedes mosquito larvae. The phytochemistry of the extracts were determined qualitatively. The test was conducted using different concentrations of 500ppm, 750ppm and 1000ppm, of the larvicidal mixture and mortalities recorded at 24, 48 and 72 hour exposure time. Data were analysed using Analysis of variance and probit analysis. Carbohydrates, tannin, flavonoid, alkaloid, and steroid phytochemicals were present in the mixture. Larval mortality was greater than 80% in all test concentrations at the 24, 48 and 72 hour exposure time. Larval mortality at the different concentrations, did not vary significantly. There was no significant variation (p>0.05) in the mortality of the larvae at different concentrations of the extracts; 500ppm, 750ppm, and 1000ppm as well as the different exposure time (p>0.05). However, a highly significant variation (p<0.01) was observed in the mortality of the larvae exposed at different concentrations throughout the 72 hour period. The calculated LC¬¬50 and LC90 at 72 hours were 123.79ppm and 459.09ppm respectively. The combined extracts of both plant materials showed very high larval potency against the Aedes mosquitoes. This mixture should be considered as possible supplementary or substitute for the control of Aedes sp. larvae.

This study investigated the distribution, species composition, and sex ratio of indoor resting mosquitoes alongside their relationship with climatic conditions in school dormitories located in Egor, Oredo and Ikpoba-okha Local Government Areas (LGAs) respectively in Benin City, Edo State, Nigeria. Indoor resting mosquitoes were collected with the aid of a sweep net and mechanical aspirator from randomly selected school dormitories between 08.00hr and 11.00hr from November (2011) to June (2012). The mosquitoes collected were identified using published morphological identification keys. A total of 766 mosquitoes containing four species: Culex quinquefasciatus (n=724; 94.5%), Anopheles gambiaes.l. (n=37; 4.8%), Culexannulioris (n=4; 0.5%) and Anopheles funestus (n=1; 0.1%) in descending order of importance, were collected. Cx.quinquefasciatus was the most predominant mosquito species in school dormitories across the three LGAs. Cx. annulioris and An. gambiaes.l were most abundant in school dormitories located in Oredo and Ikpoba-okha LGAs respectively. An.funestus occurred only in school dormitories located in Oredo LGA. Analysis of the relationship between meteorological data and species abundance varied significantly (P<0.05) only among An. gambiaes.l with rainfall. There was significant difference (P<0.05) in the sex ratio for all species obtained from the various locations except An. gambiae and Cx. annulioris in dormitories located in Oredo LGA Results of this study revealed the high presence of mosquito-borne disease risk within the school dormitories and environ, and therefore, the urgent need for properly planned, executed and regular evaluation of control measures.

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