Browsing by Author "Khamis, F.M."
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Item Detection of the Spotted Wing Drosophila, Drosophila suzukii, in Continental Sub-Saharan Africa(Springer, 2021-01-23) Kwadha, C.A.; Okwaro, L.A.; Kleman, I.; Rehermann, G.; Revadi, S.; Ndlela, S.; Khamis, F.M.; Nderitu, P.W.; Kasina, M.; George, M.K.; Kithusi, G.G.; Mohamed, S.A.; Lattorff, H.M.G.; Becher, P.G.; Swedish University of Agricultural Sciences ; International Centre of Insect Physiology and Ecology ; Kenya Agricultural and Livestock Research Organisation ; KEPHIS Headquarters ; Horticultural Crops Directorate (HCD)The spotted wing drosophila, Drosophila suzukii Matsumura, is an insect pest of soft-skinned fruit, native to Eastern Asia. Since 2008, a world-wide dispersal of D. suzukii is seen, characterized by the establishment of the pest in many Asian, American and European countries. While the potential for invasion of continental Africa by D. suzukii has been predicted, its presence has only been shown for Morocco in Northern Africa. Knowledge about a possible establishment in other parts of the continent is needed as a basis for pest management. In 2019, we carried out a first survey in three counties in Kenya to monitor for the presence of D. suzukii using traps baited with a blend of apple cider vinegar and red wine. A total of 389 D. suzukii flies were captured in a fruit farm at Nakuru county, with more female flies being trapped than males. We confirmed the morphological identification of D. suzukii using DNA barcoding. In 2020, we performed a follow-up survey at 14 locations in six counties to delimit the distribution of D. suzukii in the main berry growing zones in Kenya. The survey indicated that so far D. suzukii is restricted to Nakuru county where it was initially detected. This is the first study to provide empirical evidence of D. suzukii in continental sub-Saharan Africa, confirming that the pest is expanding its geographic range intercontinentally. Given the high dispersal potential of D. suzukii, a concerted effort to develop management strategies is a necessity for containment of the pest.Item Efficacy of Botanical Extract Formulations of Zanthroxylum Usambarense and Warburgia Ugandensis on Post-Harvest Management of Sitophilus Zeamais in Maize(MDPI, 2023-07-10) Mpoke, R.S.; Kinyua, J.; Kimani, J.W.; Ajene, I.J.; Likhayo, P.; Khamis, F.M.; International Centre of Insect Physiology and Ecology (icipe) ; Jomo Kenyatta University of Agriculture and Technology ; Kenya Agricultural and Livestock Research Organization (KALRO)Sitophilus zeamais causes significant losses to maize produce worldwide. The use of biodegradable and environmentally friendly botanicals as an alternative to synthetic pesticides is increasingly becoming important. Therefore, we sought to determine the use of plant extract formulations to manage S. zeamais during storage. Crude Zanthroxylum usambarense and Warburgia ugandensis stembark extracts were used for contact toxicity and repellent bioassays against S. zeamais. The formulations that exhibited the highest repellence and mortality were tested for insecticidal activity during storage for six months. Phytochemical profiles of the extracts were determined using GC-MS, and molecular docking of active compounds against insect target proteins was done. Mortality analyses revealed LD50 values of 114.89 μg/mL and 197.19 μg/mL for Z. usambarense’s hexane and methanol organic extracts, respectively. Warburgia ugandensis extracts had LD50 values of 69.25 μg/mL and 163.52 μg/mL, respectively. Extract formulations achieved weevil perforation index values of <50.00 in all treatments. The docking analysis showed the pesticidal potential of several compounds, and mortality could be attributed to Eugenol (19.28%), 1,8-cineole (5.78%) and Linalool (21.42%). The tested botanicals have demonstrated their ability to suppress S. zeamais development in stored maize and could be utilized to protect maize grains during storage.Item Trapping, Identification, and Rearing of Edible Palm Weevils in Kenya and Uganda(Wageningen Academic Publishers, 2021-06-15) Egonyu, J.P.; Gitonga , J.K.; Khamis, F.M.; Copeland, R.S.; Finyange, P.; Odhiambo, R.; Ddamulira , G.; Tanga, C.M.; Subramanian, S.; International Centre of Insect Physiology and Ecology ; Kenya Agricultural and Livestock Research Organization,, Matuga, Kwale ; Kenya Agricultural and Livestock Research Organization, Alupe, Busia ; National Crops Resources Research InstitutePalm weevils, Rhynchophorus spp. (Coleoptera: Curculionidae) double as devastating invasive pests of palms, and delicacies in many communities. This study evaluated ethyl acetate and 3-methyl-octan-4-ol for trapping palm weevils from coconut, oil and raffia palms in Kenya and Uganda; taking into account the distance of traps on oil palm from a forest or raffia palm. Eggs from the weevils from different locations were incubated and their larvae reared on sugarcane under laboratory conditions. All the 285 weevils collected were identified by morphological and molecular techniques as Rhynchophorus phoenicis, and the catch was female-biased. 3-methyl-octan-4-ol attracted more weevils than ethyl acetate. More weevils were caught at ~100 m away from the forest than within 15 m outside the forest; and on raffia palm than oil palm irrespective of distance apart. Eggs took ~4 d to develop and 95-100% of pupae developed into adults, irrespective of the collection site. Larval and pupal developmental periods for weevils from Uganda were longer than those of Kenya, resulting in egg-adult development of ~6 months and ~4 months, respectively. The sex ratio of laboratory produced males and females was similar. These results can guide in designing an integrated R. phoenicis management system with a dual benefit of protecting palms from weevil attack and utilising the weevils to improve human nutrition.
