Fusarium wilt disease of tomato is caused by Fusarium oxysporum f. sp. lycopersici and is a limiting factor to tomato production in Nigeria. The objectives of this study were to screen tomato varieties commonly cultivated in Nigeria to determine their host resistance status to F. oxysporum, identify fungi species associated with tomato plants showing Fusarium wilt symptoms and the in-vitro evaluation of aqueous and methanol extracts of four botanicals for bioactivity. Symptomatic sample plants were collected from three farms in tomato producing communities of Nigeria. Isolation was done by direct plating method on acidified Potato Dextrose Agar (PDA). Fungi isolates were identified by cultural and microscopic characteristics. Extracts were prepared and evaluated for bioactivity by agar dilution method. The experiment was laid in a Completely Randomized Design replicated three times. Data were analyzed by descriptive and statistical analysis. Significantly different means were separated using Least Significant Difference at 5% level of significance. Of the nine varieties evaluated, only Tomato Shanty+N showed moderate resistance to F. oxysporum, while others were susceptible. Fungi isolated from symptomatic plants were Colletotrichum spp, Curvularia lunata, Sclerotia rolfsii, Rhizopus spp, Pestalocia macrotrica, Aspergillus spp, and Fusarium oxysporum. Extracts showed bioactivity against F. oxysporum at different concentrations. Methanol as solvent in preparing of Azadirachta indica leaf extract showed the highest inhibitory properties against F. oxysporum at low concentration. This was followed by Morinda lucida and Tagetes erecta at 37.5% and 25% concentration respectively. Tomato shanty+N and low concentration methanol extracts of Azadirachta indica leaf (12.5%) are therefore recommended.

An experiment was carried out to evaluate the fungitoxic effect of Trichoderma longibrachiatum (Rifai) metabolite on F. oxysporum, A. niger and A. tamarii. The fungi were collected from the International Institute of Tropical Agriculture (IITA) and Nigerian Institute of Science Laboratory Technology (NISLT). T. longibrachiatum was cultured on 1/4 strength Potato Dextrose Broth (PDB) following standard procedures. Its metabolite was extracted using 50 ml n-hexane with 50 ml Potato Dextrose Broth (PDB). The metabolite was purified by filter sterilization using a sterile 0.22 millipore filter disc after centrifuging at 900 rpm for 20 minutes. Petri plates of each fungus were later impregnated in triplicates with the T. longibrachiatum metabolites using four concentrations (10%, 25%, 50% and 100%), and three volumes (1 ml, 2 ml, and 3 ml). Petri plates of fungi without the metabolite and Petri Plates of fungi with n-hexane and PDB served as control. All Petri Plates were incubated at 28˚C for 7 days. Radial and diametric growth of each fungus on all Petri Plates were taken daily at 24 hours intervals. Data obtained were analysed using SAS (version 9.3). Growth inhibition of F. oxysporum, A. niger and A. tamarii was significantly higher than in control in that order (P ≤ 0.05). Inhibition of the fungi by metabolites extracted with both PDB and n-hexane was significantly better than in control. Generally, inhibition by metabolite extracted with PDB was better than that extracted with n-hexane. Growth inhibition at all the concentrations of the metabolite was significantly better than in the control (P ≤ 0.05

Introduction: Cashew (Anacardium occidentale L.) is an important tree crop and seedling survival is pertinent to successful establishment. Cashew seedling is infected by blight pathogens causing more than 60% seedling lost, however pesticides residues related issues and high cost of chemical necessitate efficacy trials of aqueous extracts of Mangifera indica, Azadirachta indica and Hyphtis suaveolens evaluated in-vitro on associated pathogens. Methods: Flora of blight-infected cashew seedlings was randomly collected from Cocoa Research Institute of Nigeria (CRIN) nursery between July and October, 2019. Mycoflora analysis was carried out in the plant pathology (Mycology) laboratory of CRIN. Antifungal assay of powdered Mangifera indica, Azadirachta indica and Hyphtis suaveolens were screened using aqueous extracts at 1:4 (w/v). Potato Dextrose Agar (PDA) amended with 1ml of 100%, 75%, 50%, 25%, and 0% of the extracts and Mancozeb (synthetic fungicide) as standard, 5mm mycelia mat disc of 10day old each of Lasiodiplodia theobromae, Fusarium pallidoroseum and Macrophomina sp. were placed at the centre of the amended media in triplicate and incubated 5-7days using complete randomized design (CRD). Mycelia extension inhibition and percentage growth inhibition (R) obtained. Results: Aspergillus niger, A. flavus, Fusarium oxysporium, F. pallidoroseum, Lasiodiplodia theobromae., Pythium sp., Rhizopus sp., Macrophomina sp. and Rhizotonia sp. were isolated. Fusarium pallidoroseum, L. theobromae and Macrophomina sp. screened with the varied concentrations of botanicals showed reduction in mycelia diameter; Mangifera indica (31.50%), A. indica (48.70%) and H. suaveolens (25.86%) on F. pallidoroseum favorably competed with mancozeb (39%) at 25% concentration while only M. indica was significant on L.theobromae(64.12%)and Macrophomina sp.(40.29%) and significantly different from control (0%). Conclusion: Aqueous extracts of M. indica, A. indica and H. suaveolens showed fungicidal potential on F. pallidoroseum and M. indica was significant on L. theobromae and Macrophomina sp.

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