Insecticidal activity and phytochemical analysis of Pyrus communis L. extracts against malarial vector, Anopheles pharoensis Theobald, 1901 (Diptera: Culicidae)

We aimed at investigating the insecticidal activity of Pyrus communis L. against the malarial vector, Anopheles pharoensis Theobald, 1901 and its phytochemical constituents. Leaves were collected and the crude extracts were prepared using hexane (PCH) and methanol (PCM). Tested PCH and PCM possess larvicidal activity against A. pharoensis with LC50 and LC90 values of 179.9, 41.2 and 314.1, 68.9 ppm, respectively. A significant reduction in the number of eggs laid by females A. pharoensis that developed from larvae treated with PCH and PCM was noticed. Also, PCH treatment showed highest repellent activity compared with PCM. GC/MS analysis of the PCH revealed the presence of 55 identified compounds subdivided into 2 major classes viz. phenyl alkanes (38.65 %) and oxygenated sesquiterpenoids (36.41 %). LC/MS of PCM had led to the identification of 37 compounds, mainly flavonoids, chalcones, phenolic acids and tannins. The results demonstrate the insecticidal potential of leaves methanol and hexane extracts from P. communis as green insecticidal agents for the control of malarial vector, A. pharoensis.

Mosquito Larval Species and Geographical Information System (GIS) Mapping of Environmental Vulnerable Areas, Dakhla Oasis, Egypt

Aims: This paper investigates the spatial distribution of mosquito breeding sites within the Dakhla oasis of the Western Desert of Egypt. Study Design: GIS spatial analysis was used to map the area under risk of mosquito proliferation. Place and Duration of Study: Dakhla oases, during September 2009 to October 2010. Methodology: Landsat images, synchronized with mosquito larval survey, were processed to identify the vegetation status of the study area. Twenty-two locations distributed in Dakhla oasis were investigated as nine mosquito species were collected from drains, paddle fields, and waterlogged areas. Results: Results showed that the main vector of Malaria disease (Anopheles pharoensis and Anopheles sergentii), as well as the Culex pipiens, which is the main vector of filarial disease are abundant. Further, the geo-environmental setting and the discharge of increasing cultivated areas develop considerable waterlogging and pond areas, which are favorable breeding sites of mosquito. In Dakhla oases, the produced risk map showed that a large part of urban and cultivated regions were at risk of mosquito spread. Conclusion: It was concluded that mosquito larval populations fluctuated with the dynamics of vegetation cover in Dakhla. Multi-year data of mosquito collections are still required to provide a better characterization of the abundance of these insects from year to year which can potentially provide predictive capability of their population density based on remotely sensed ecological measurements.