Field evaluation of the bioefficacy of diflubenzuron (Dimilin (R)) against container-breeding Aedes sp mosquitoes

The inhibitory activity of diflubenzuron, a chitin synthesis inhibitor, on the ecdysis of Aedes sp. larvae was evaluated in earthen jars and automobile tires. Two formulations of diflubenzuron were used in this study: Dimilin (R) WP (wettable powder), 25 and Dimilin (R) GR (granular), 2. The equivalent rate of 25 g/ha, 50 g/ha and 100 g/ha active ingredients for both WP and GR formulations were used in this study. Generally, at the higher dosage of 100 g/ha, both formulations were more effective against Aedes mosquitoes. On the whole, the WP formulation appeared to perform better than the GR formulation in terms of residual activity

Bacteria Fauna from the House Fly, Musca domestica (L.)

The house fly, Musca domestica has long been considered a potential agent for disease transmission ever since its existence. The general truth of this assertion remains undisputed till the present day in spite of increasing awareness toward an improved sanitation and better hygiene. The habitual movement of house fly from filthy substrata such as human faeces, animal excreta, carcasses, garbage, etc. makes them ideal candidates for disease transmission such as cholera, shigellosis, salmonellosis and others when settling on food. Fly as a potential mechanical vector of pathogenic bacteria was elucidated in this study by examining flies from various breeding sites such as food courts, dumping ground, food processing areas and poultry farm in Peninsular Malaysia. The flies were baited with 10 sugar solution on a glass slide in the field. All materials used for collection of samples were sterile. Bacteria from fly sample were isolated using the normal isolation technique. Bacillus sp., Coccobacillus sp., Staphylococcus sp., Microccus sp., Streptococcus sp., Acinetobacter sp., Enterobacter sp., Proteus sp., Escherichia sp., Klebsiella sp. and yeast cells were isolated from feaces, vomitus, external surfaces and internal organs of house fly. Newly emerged house fly did not harbour any bacteria

Comparative oviposition preferences of Aedes (Stegomyia) aegypti (L.) to water from storm water drains and seasoned tap water

The comparative oviposition preferences of Aedes aegpti to water from storm-water drains and seasoned tap water were evaluated in the laboratory. The sample was collected from concrete storm-water drains with stagnant clear water in a dengue-endemic site, Taman Samudera, Selangor. Ae. aegypti adults were given a blood meal and released into the caged. Gravid females were given a choice between drain water and seasoned tap water for egg deposition. In a no-choice test, there was no significant difference in the numbers of eggs, larvae, pupae and adults colonized from the drain water and seasoned tap water (p>0.05), indicating that Ae. aegypti oviposit their eggs on a substrate which is readily available. In a choice test, the number of eggs laid by Ae. aegypti in drain water (1630.67 ± 204.26) was significantly more than that in seasoned tap water (221.33 ± 53.18) (p0.05), indicating that water from the drain did not contain high organic content. Significant water conductivity (p<0.05) and the presence of bacteria could have contributed to the site selection for egg laying by Ae. aegypti. The drain water successfully supported the colonization of the immatures, with the emergence of 824.33 ± 13.96 adult mosquitoes. The ratio of male and female mosquitoes was 1:1. This study concluded that the concrete drainage system with clear stagnant water provides a suitable medium for the colonization of dengue vector Ae. aegypti