Browsing by Author "Kasina, 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 Effect of Extraction Ingredients on the Conformation and Stability of Silk Sericin (SS)(MDPI, 2022-10-01) Muindi, M.P.; Lee, J.H.; Kweon, H.; Kasina, M.; Kenya Agricultural and Livestock Research Organization - National Sericulture Research Center ; National Institute of Agricultural SciencesSilk sericin (SS) has different physicochemical properties depending on the extraction technique. In this study, SS was isolated in the presence of ingredients, including 5 to 10% ethanol (EtOH) and 5 to 10% glycine. Furthermore, temperature conditions of 80 °C, 100 °C, and 120 °C were used for 1, 3, and 5 h to evaluate the extraction rates. The extraction, gelation, structural, and cytotoxicity properties of SS extracted under different conditions were investigated. Extraction at 100 °C and 120 °C were found to have the highest SS yield, with 80 °C being the lowest. SS isolated at 100 °C and 120 °C for 1 and 3 h in water, and EtOH gelled at 4 °C in 2 to 3 days and 37 °C in 40 min. Glycine SS extracts were obtained at 100 °C and 120 °C for 1 h, gelled at 4 °C for 20 days and 37 °C for 16 h. SS was observed at 80 °C, with no gelation occurring. Glycine SS extracts obtained for 3, and 5 h at 120 °C showed no gelation. Circular dichroism (CD) results show glycine in SS induces α-helix and random coil structure. SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and fast performance liquid chromatography (FPLC) were used to quantify the molecular weight distribution at 63 and 70 kDa, respectively. The MMT assay (3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) revealed no cytotoxicity in macrophage RAW 264.7 cells treated with this method SS; these findings present the significance and possibility of using selected extraction ingredients in SS that allow for the application of native SS at an initial extraction viscosity.Item Genomes of the Cosmopolitan Fruit Pest Bactrocera Dorsalis (Diptera: Tephritidae) Reveal its Global Invasion History and Thermal Adaptation(Elsevier B.V., 2023-11) Zhang, Y.; Liu, S.; de Meyer, M.; Liao, Z.; Zhao, Y.; Virgilio, M.; Feng, S.; Qin, Y.; Singh, S.; Wee, S.K.; Jiang, F.; Guo, S.; Li, H.; Deschepper, P.; Vanbergen, S.; Delatte, H.; van Sauers-Muller, A.; Syamsudin, T.S.; Kawi, A.P.; Kasina, M.; Badji, K.; Said, F.; Liu, L.; Zhao, Z.; Li, Z.; China Agricultural University ; Ministry of Agriculture and Rural Affairs ; Royal Museum for Central Africa ; Punjab Agricultural University ; University Kebangsaan Malaysia ; Chinese Academy of Inspection and Quarantine ; CIRAD UMR PVBM ; Ministry of Agriculture ; Bandung Institute of Technology ; Port Moresby ; Apiculture Research Institute ; Crop Protection Directorate ; Abdul Wali Khan University MardanIntroduction. The oriental fruit fly Bactrocera dorsalis is one of the most destructive agricultural pests worldwide, with highly debated species delimitation, origin, and global spread routes. Objectives. Our study intended to (i) resolve the taxonomic uncertainties between B. dorsalis and B. carambolae, (ii) reveal the population structure and global invasion routes of B. dorsalis across Asia, Africa, and Oceania, and (iii) identify genomic regions that are responsible for the thermal adaptation of B. dorsalis. Methods. Based on a high-quality chromosome-level reference genome assembly, we explored the population relationship using a genome-scale single nucleotide polymorphism dataset generated from the resequencing data of 487 B. dorsalis genomes and 25 B. carambolae genomes. Genome-wide association studies and silencing using RNA interference were used to identify and verify the candidate genes associated with extreme thermal stress. Results. We showed that B. dorsalis originates from the Southern India region with three independent invasion and spread routes worldwide: (i) from Northern India to Northern Southeast Asia, then to Southern Southeast Asia; (ii) from Northern India to Northern Southeast Asian, then to China and Hawaii; and (iii) from Southern India toward the African mainland, then to Madagascar, which is mainly facilitated by human activities including trade and immigration. Twenty-seven genes were identified by a genome-wide association study to be associated with 11 temperature bioclimatic variables. The Cyp6a9 gene may enhance the thermal adaptation of B. dorsalis and thus boost its invasion, which tended to be upregulated at a hardening temperature of 38 °C. Functional verification using RNA interference silencing against Cyp6a9, led to the specific decrease in Cyp6a9 expression, reducing the survival rate of dsRNA-feeding larvae exposed to extreme thermal stress of 45 °C after heat hardening treatments in B. dorsalis. Conclusion. This study provides insights into the evolutionary history and genetic basis of temperature adaptation in B. dorsalis.Item Growing Cabbage (Brassica Oleracea Var. Capitata) Under Low Cover Agronets Prevents Pest Infestation and Increases Yields in Kenya(African Phytosanitary Journal, 2023-07-30) Kasina, M.; Guantai, G.; Mbugi, J.; Mwaniki, S.; Wasilwa, L.; Kipyab, P.; Ngouajio, M.; Kenyatta University ; Kenya Agricultural and Livestock Research Organization ; Kenya Plant Health Inspectorate Service Headquarters ; Michigan State University ; Cirad UR HortsysCabbage (Brassica oleracea var. capitata) is an important vegetable crop in Kenya both in production and income provision to smallholder farmers. Pests are serious hindrance to its production and most farmers rely on synthetic insecticides. Such reliance has negative effects on non-target organisms, environment, animal and human health. This study was carried out from May to October 2011 to determine impact of low cover nets of different mesh size and cover duration on reducing cabbage pest infestation and yields. The study was conducted at Kenya Agricultural Research Institute Kabete and Practical Training Centre Thika based on a randomized complete block design with five replicates. Treatments included Agronets of fine (0.4mm) and large (0.9mm) mesh covered over the crop permanently (season-long) or temporarily (opened three times a week from 9am to 3pm) and control where no Agronet was used. The results show that the number and damage by diamondback moth (DBM) was significantly lower on cabbages grown under the Agronets compared with control. Infestation by thrips was lower on cabbages grown under permanent cover compared with those under temporal cover and without cover. However, there was no significant difference of aphids infestation. The marketable yield was significantly higher on cabbages grown under the Agronets, recording about 17% yield loss compared with control that recorded about 90% yield loss. The study concludes that Agronets provide an important component of integrated pest management strategy for cabbage production in Kenya with high crop yields benefit and highly recommended for application by growers.Item The Importance of African Honey Bees (Apis MeliferaL.) As Pollinators of High Value Crops in Kenya: A Case of Butternut Squash (Cucurbita Moschata Duchesne Ex Poir.) Pollination(2013) Martius, C.; Kraemer, M.; Wittmann, D.; Kasina, M.; Nderitu, J.Butternut squash (Cucurbita moschata Duchesne ex Key words: Fruit yield,Hypotrigona spp, halictid bees,Poir.) is a high value crop in Kenya grown mostly by pollination smallholder farmers as a main source of household income, targeting urban market. Prior to this study,there was no information about its pollinators in the country and farmers do not manage its pollination. We documented butternut squash flower visitors and their behavior during foraging periods and evaluated their pollination efficiency in terms of yield as the end point. The study was done at Kakamega, a high potential area for agriculture in western Kenya where butternut squash seeds were planted in 15m xiS m plot. About 50 flowers were bagged to prevent pollinators while a similar number was left open for unlimited visits. Individuals of honey bees (Apis mellifera L.), Halictid bees (Halictidae), stingless bees (Hypotrigona spp), ants (Formicidae) and hover flies (Syrphidae) were observed visiting flowers. It was only honey bee visitation that was sufficient to effectively pollinate butternut squash flowers. Higher honey bee visitation rates were observed on female flowers compared with male flowers. Fruit and seed yields were significantly higher (P<0.05) in flowers with unlimited bee visits compared with hand pollination possibly due to challenges in timing pollen maturity and stigma receptivity. This study shows that honey bees should be protected to ensure crop (butternut squash) pollination. The recent reports of declining honey bee colonies due to parasites and diseases, climate change, pesticide use and reduction of food resources should be taken seriously as this threatens crop production and hence food security. Farmers growing butternut squash are advised to keep or rent honey bees for pollination of their crop during blooming period to guarantee them quantity and quality yields. In addition, policies to support use of honey bees for crop production in Kenya should be developed and implemented to ensure information on pollination of crops including butternut squash forms part of the extension messages to farmers.Item Interactions Between Integrated Pest Management, Pollinator Supplementation, and Normalized Difference Vegetation Index in Pumpkin, Cucurbita Maxima (Cucurbitales: Cucurbitaceae), Production(Oxford University Press, 2023-05-12) Waithaka, N.A.; Kasina, M.; Samita, N.E.; Guantai, M.M.; Omuse, E.R.; Toukem, N.K.; Lattorf, M.G.; Abdel-Rahman, E.M.; Adan, M.; Mohamed, S.A.; Dubois, T.; Kenyatta University ; Kenya Agricultural and Livestock Research Organization (KALRO) ; Kenya Plant Health Inspectorate Service (KEPHIS) ; International Centre for Insect Physiology and Ecology (icipe) ; University of Pretoria ; University of NairobiSustainable production of pumpkin (Cucurbita maxima Duchesne) partly relies on integrated pest management (IPM) and pollination services. A farmer-managed field study was carried out in Yatta and Masinga Sub-Counties of Machakos County, Kenya, to determine the effectiveness of a recommended IPM package and its interaction with stingless bee colonies (Hypotrigona sp.) for pollinator supplementation (PS). The IPM package comprised Lynfield traps with cuelure laced with the organophosphate malathion, sprays of Metarhizium anisopliae (Mechnikoff) Sorokin isolate ICIPE 69, the most widely used fungal biopesticide in sub-Saharan Africa, and protein baits incorporating spinosad. Four treatments—IPM, PS, integrated pest and pollinator management (which combined IPM and PS), and control—were replicated 4 times. The experiment was conducted in 600 m2 farms in 2 normalized difference vegetation index (NDVI) classes during 2 growing seasons (October 2019–March 2020 and March–July 2020). Fruits showing signs of infestation were incubated for emergence, fruit fly trap catches were counted weekly, and physiologically mature fruits were harvested. There was no effect of IPM, PS, and NDVI on yield across seasons. This study revealed no synergistic effect between IPM and PS in suppressing Tephritid fruit fly population densities and damage. Hypotrigona sp. is not an efficient pollinator of pumpkin. Therefore, we recommend testing other African stingless bees in pumpkin production systems for better pollination services and improved yields.
