International Journal of Research Publication and Reviews, Vol 6, Issue 7, pp 1192-1199 July 2025 International Journal of Research Publication and Reviews Journal homepage: www.ijrpr.com ISSN 2582-7421 Isolation and Control of Fungal Post Harvest Rot Pathogens of Cucumber (Cucumis Sativus) using Ethanolic Leave and Stem Bark Extract of Jatropha Tanjorensis Emmanuel Francis Mathematics Programme, National Mathematical Centre, Abuja, Nigeria efrancis@nmc.edu.ng ABSTRACT: The study attempted to find out Isolation and Control of Fungi Associated with rot of cucumis sativum using ethanolic leaves and stem bark extracts of Jatropha tanjorensis in Mubi Local Government Area, Adamawa State. Total number of samples of spoilt of cucumber and healthy ones (5) of them were collected from the Mubi market metropolis and transported to botany laboratory Adamawa State University, Mubi. Potatoes Dextrose Agar (PDA) was the culture media used for the isolation of fungi from the sampled cucumber and the preparation of pure culture. A technique was used for the identification of the isolated fungi. Pathogenicity test was carried out in order to know if the isolated fungi were really responsible for the spoilage of the cucumber. The preparation of the ethanolic leave and stem bark extract was carryout by the procedures described. The extract was prepared into three different concentrations ranging from 200-600mg/ml (i.e. 200, 400 and 600mg/ml). The agar plate diffusion method was used to determine the growth of inhibition of fungi isolated by plant extract. The data on the average zone of inhibition produced was analyzed using ANOVA with the help of Statistical Package for Social Sciences (SPSS). Result from the study showed that two (2) pathogens were identified to be responsible for the rot of cucumber in mubi R microsphorus and R-stolonifer. The result further revealed both ethanolic leave and stem bark extract of Jactroph tanjorensis has an effect on both pathogens isolated from the sample but the ethanolic leaves extract is more effective than stem bark it concluded that R-microphorus R-stolonifer are pathogens causing rot in cucumber in Mubi market, Ethanolic leave and stem bark extract was found to be effective in inhibiting the growth of pathogens. Keywords: Isolation and Control, Fungi, Cucumber, Ethanolic Leave, Stem Bark Extract 1. Introduction Fruits are the consumable part of mature ovary of flowering plants which are normally eaten raw fruits also includes many structures that are not commonly called fruits such as bean pods, corn kernels, tomatoes and wheat grains (Ikhiwili, 2012). It is impossible to overstate the significance of fruits in human nutrition as they supply vital growth elements like vitamins and minerals required for healthy metabolism (Al-Hindi et al., 2011). Fruits are becoming the primary dietary source for both humans and many animals (Lewis, 2022). However, throughout the storage period, fruits often have an active metabolism and are prone to spoiling (Singh et al., 2007). The effective development and survival of different parasitic and saprophytic types of fungus are also facilitated by the low pH, high concentrations of different carbohydrates, minerals, vitamins, and amino acids (Droby 2006). According to yearly studies, 20% of cultivated fruits and vegetables perish. (Barth et., al 2009) particularly after harvest (Singh et al., 2007). This has been linked to spoiling fungus, which can be harmful or toxic. (Lewis, 2022), Previous studies have found and isolated toxins-producing fungus from damaged fruits (Al-Hindi et al., 2011). There have been reports of pathogenic fungus in allergy or infection patients (Droby, 2006). Mycotoxins and other poisonous metabolites produced by Aspergillus species can be dangerous to people and animals everywhere (Droby, 2006). Cucumber (Cucumis sativus.) is a major vegetable consumed mainly as salad and pickle. Although Cucumbers are used to make pickles all throughout the world, they are mostly eaten as salad in underdeveloped nations like Nigeria. Cucumber's high water content (about 95%) makes it a great cooling vegetable and a strong source of potassium, calcium, vitamin A, and vitamin K. In nature, cucumbers are quite perishable. Since cucumbers are prone to shrivelling, 90–95% humidity should be maintained during marketing, transportation, and storage (Dhall et al., 2010). Postharvest rot disease prevalence, pathogen frequency, and the relative importance of different pathogens as decay-causing agents may differ between geographic regions. This is due to the fact that different environments, crop physiology, harvesting methods, and storage conditions can cause microbial diseases to impact crops in different ways. Therefore, it is crucial to identify the fungal pathogens causing the illness in a given area in order to create an efficient disease management program for Hausa potatoes. Furthermore, the development control techniques are essential for reducing food losses due to microbial assault and preventing microbial spoiling.