Browsing by Author "Mwongeli M.F."

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Prevalence And Characterization of Avocado Fruit Fungal Diseases in Embu County, Kenya, And the Efficacy of Aloe Secundiflora Crude Extracts in Their Control
(Chuka University, 2023) Mwongeli M.F.; Githae E.W; Mwangi J.M
Avocado production faces various constraints that include common post-harvest fungal diseases. Most of these diseases are difficult to control using cultural measures while use of chemicals leads to pathogen reistance in addition to being harmful to human and environment. The objective of this study was therefore to determine the prevalence of the fungal avocado fruit diseases in Embu County, isolate and characterize the causal pathogens and test the efficacy of Aloe secundiflora extract in the diseases. Questionnaires were administered to a total of 120 respodents to gather additional information on avocado production, marketing and management. The stores and avocado bags were randomly identified and the fruits assessed for the prevalence of fungal avocado diseases. Aloe leaves were collected in the field and phytochemical analysis done using standard procedures. The efficacy of Aloe secundiflora extract against the avocado fungal diseases was done in the laboratory using a Completely Randomized Design. The extracts were then assessed for antimicrobial activity against Colletotrichum gloeosporioides (scab disease), Sphaceloma perseae (anthracnose) and Cercospora purpurea (Cercospora spot). In the results, chemicals were widely used to control the pathogens. The mean percentage prevalence of scab, cercospora spot and anthracnose diseases was 36.4%, 35.15% and 35.0%, respectively, among the markets, although anthracnose was highly prevalent within each market. Four avocado varieties were commonly sold with Fuerte and Puebla being the most susceptible to the fungal diseases. There were significant variations in the morphological characteristics of the pathogen isolates. The aloe extract revealed the presence of steroids, phenolics, flavonoids, saponins, terpenoids and phenolics. The extract prepared using ethanol had a high inhibitory activity against C. gloeosporioides (15.59mm) and Cercospora purpurea (7.22mm), while hexane solvent extract had minimal antimicrobial activity (10.53 and 5.22mm respectively). Aloe crude extract is therefore a potential antifungal agent against C. gloeosporioides and Cercospora purpurea.
Prevalence of post-harvest fungal diseases of avocado in fruit markets in Embu County Kenya
(African Research Journal of Biosciences, 2024-01-25) Mwongeli M.F.; Mwangi J.M.; d Githae E.W
Avocado fruit is highly valued for its nutritional benefits and industrial uses. Production of avocado contributes to poverty alleviation, food security, and economic growth in producing countries. However, production is hindered by fungal diseases such as anthracnose, scab and cercospora spot. This study assessed the prevalence of the aforementioned fungal diseases in various fruit markets in Embu County. A cross-sectional survey was done involving 120 fruit vendors across six markets. Avocado fruits were randomly selected and examined for the presence of anthracnose, scab and cercospora spot diseases. Symptomatic fruits were taken to the laboratory for further analysis. The Hass avocado was the most common variety, found in 39% of the sampled stores, followed by local varieties (24%), Fuerte (21%), and Puebla (4%). Most vendors (42%) used hooks to harvest avocados, while 39% picked the fruits by hand. For packaging, 54% used sacks, 21% used buckets, and 13% used crates. Fifty-four percent of vendors used synthetic fungicides for disease management, while others employed various cultural practices. Disease prevalence varied significantly (P < 0.05) across the markets. Kianjokoma market had the highest prevalence of anthracnose (35.0%), while Mutunduri had the lowest (21.3%). Siakago market recorded the highest prevalence of scab (36.3%), with Mutunduri again having the lowest (20.7%). Cercospora spot was most prevalent in Kianjokoma (35.0%). The study highlights widespread avocado fruit diseases, exacerbated by harvesting and post-harvest handling practices. Training farmers on post-harvest disease management could significantly reduce associated losses.