Browsing by Author "Mucheru, Obadiah"

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    Potential Effects Of Pyrethrin Incorporated In Sucrose Baits Against Phlebotomus Duboscqi Neveu Lemaire (diptera: Psychodidae) In Leishmaniasis Control Strategies
    (Webmedcentral, 2010-11-06) Ireri, Laban N.; Mucheru, Obadiah; Ngure, Peter Kamau; Kepha, Stella; Kimutai, Albert; Cirindi, Josyline; Tonui, Willy K.
    Background: Due to challenges of controlling leishmaniasis in Kenya through the vector, the efficacy of pyrethrin EC (Pymos™ 0.6% W/V) a mosquito adulticide was evaluated against Phlebotomus duboscqi while incorporated in sucrose as a possible complementary method. Methods: Pyrethrin was prepared into concentrations of 0.08, 0.25and 0.5 mg/ml using 10% sucrose. Ten male and female sand flies were each aspirated into jars and fed separately with the prepared solutions using cotton wool pads placed atop experimental jars and mortality monitored each day. The experiments were replicated three times. Results: Significant mortality (P< 0.05) for both sexes was observed. The concentration of 0.08mg/ml gave low adult mortality in 24 hours but amplified with time. In the 0.25 bioassay, mortality of females were 10 (33.3%) and males had 21 (70%) in 24 hours. The LD50 for females and males tied at 0.1 mg/ml in 48 hours of exposure. The concentration of 0.25 mg/ml was ideal at 48 hours of feeding where majority of the sand flies succumbed to the insecticide. There were significant mortality differences (P <0.05) between the concentrations but no significant difference (P>0.05) was observed in male and female mortality at 48 hours of exposure however. Although we cannot rule out sand fly mortality due to contact with the test material, the results of this study however suggest that control strategies using low-dose pyrethrin-sugar combinations as baits may be effective against phlebotomine sand flies and other sugar feeding pests of medical importance.
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    The potential of the extracts of Tagetes minuta Linnaeus (Asteraceae), Acalypha fruticosa Forssk (Euphorbiaceae) and Tarchonanthus camphoratus L. (Compositae) against Phlebotomus duboscqi Neveu Lemaire (Diptera: Psychodidae), the vector for Leishmania major Yakimoff and Schokhor
    (Journal of Vector Borne Diseases, 0201-09) Ireri, Laban N.; Kongoro, Jedida; Ngure, Peter Kamau; Mutai, Charles; Langat, Bernard; Tonui, Willy K.; Kimutai, Albert; Mucheru, Obadiah
    Background & objectives: Harmful effects of synthetic chemical insecticides including vector resistance, environmental pollution and health hazards have necessitated the current significance in the search for plant-based insecticide products that are environmentally safe and effective to leishmaniases control. The insecticidal activity of Tagetes minuta Linnaeus (Asteraceae), Acalypha fruticosa Forssk (Euphorbiaceae) and Tarchonanthus camphoratus L. (Compositae) extracts were investigated against Phlebotomus duboscqi Neveu Lemaire (Diptera: Psychodidae). Methods: The extracts were prepared from dried aerial parts soaked in methanol and ethyl acetate twice until the filtrates became clear, filtered and dried out by rotary evaporation at 30–35oC. The solid extracts obtained were later prepared into 2.5, 5 and 10 mg/ml. Two millilitres of the solutions were blotted on filter papers, which were dried overnight and placed into jars where adult sandflies were aspirated. Males and females were assayed separately. Results & conclusion: The extracts had significant mortality (p<0.05) in both males and females bioassays but were not significantly different between sexes. The extracts of Acalypha fruticosa and Tagetes minuta had significantly higher mortality rates than those of Tarchonanthus camphoratus and the different concentrations used showed significantly different mortality rates and 10 mg/ml was the most effective concentration. Cent percent mortality was obtained at 96 h of exposure to 5 and 10 mg/ml concentrations except for Tarchonanthus camphoratus which had a mortality of only 46.7% in 10 mg/ml bioassay. These extracts were found to be insecticidal to adult sandflies.