Browsing by Author "Wagacha, John M."

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    Impact of push–pull cropping system on pest management and occurrence of ear rots and mycotoxin contamination of maize in western Kenya
    (2020-08-18) Njeru, Nancy K.; Midega, Charles A. O.; Muthomi, James W.; Wagacha, John M.; Khan, Zeyaur R.
    Push–pull involves intercropping of cereals with Desmodium as a “push” crop and planting Napier grass/Brachiaria as the “pull” crop at the border. The technology has been reported to effectively control stemborers, striga weed, and fall armyworm (FAW), and to improve soil nutrition, resulting in increased grain yield. This study evaluated the impact of stemborer and FAW management using this technology on incidence of maize ear rots and preharvest contamination of grains with aflatoxin and fumonisin in western Kenya. The study was conducted during three cropping seasons on maize grown under the push–pull system and as a monocrop. Incidence of stemborer and FAW damage was determined as percentage of damaged plants, while incidence of ear rots was determined as percentage of ears with symptoms. At harvest, fungi were isolated from kernels and aflatoxin and fumonisin were quantified using enzyme-linked immunosorbent assay. Stemborer and FAW damage was significantly (p = .001) reduced by over 50% under the push–pull system. There was also a significant (p < .001) reduction in the incidence of Fusarium verticillioides (60%) and Aspergillus flavus (86%), which was reflected in a reduced incidence of ear rots (50%) with the push–pull system (p = .001). Fumonisin in maize from push-pull farms was significantly (p = .048) reduced (39%) but the technology had no significant (p > .05) effect on aflatoxin. The study showed that push–pull is an effective strategy for managing maize ear rots and fumonisins, and therefore could play a role in improving food safety among smallholder maize farmers in the region.
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    Publication
    Isolation of Actinomycetes from Geothermal Vents of Menengai Crater in Kenya
    (International Journal of Molecular Biology, 2017-07-20) Waithaka, Paul Njenga; Mwaura, Francis; Wagacha, John M.; Gathuru, Eliud Mugu
    The current study was carried out to isolate actinomycetes from the geothermal vents of Menengai crater. Soil samples were collected from vents A and D in sterile polythene papers and transported to Egerton University, Department of biological sciences laboratories. The samples were air dried on the benches for one week. To kill vegetative bacteria, the soil samples were heat in a hot air oven for 1h before serial dilution to 10-6. The samples separately plated on Starch casein agar, Luria Bertani agar and starch nitrate agar in which nystatin and nalidixic acid had been added to reduce the growth of fungi and other types of bacteria. Incubation was carried out at 30 o C for up to a period of one Month. The isolated actinomycetes were characterized by cultural, morphological and biochemical means. There was no significant difference in the number of actinomycetes isolated between vents A and vents D(P=0.439). However, the number of actinomycetes isolated using the three isolation media varied significantly (F=37, P=0.03). Totally, 16 actinomycetes were isolated from the vents. It is recommended that the isolates be tested for antagonism against pathogenic microorganism.