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Management of Fusarium wilt disease of tomato (Solanum lycopersicum L.) using selected plant extracts
(Conscientia Beam, 2021) Aduramigba-Modupe, A. O.; Alawiye, T. T.; Adedire, O. M.
Fusarium wilt, caused by Fusarium oxysporum f. sp. lycopersici (Sacc.) Snyder and Hansen, is considered the most widespread, prevalent and economically damaging fungal disease of tomato in Nigeria. This study was conducted to isolate and identify fungal pathogens associated with tomato wilt disease, and to evaluate the efficacy of four plant extracts in the management of wilt disease in vitro and in vivo. Two tomato varieties, Roma VF and UC 80, were used for the biocontrol assay.
Four plant extracts, Zanthoxylum zanthoxyloides roots, Distemonanthus benthamianus stems, Azadirachta indica seeds and Oryza sativa husk, were evaluated against Fusarium oxysporum f. sp. lycopersici. Three concentrations (0.03, 0.04 and 0.05 g/mL) of each extract were investigated using the agar dilution method for radial growth inhibition assay. Of the four plant extracts evaluated, Oryza sativa husk extract was the most effective in inhibiting the growth of Fusarium oxysporum, both in vitro and in vivo.
Rice husk extract (0.05 g/mL) had the highest inhibition rate (100%), followed by Azadirachta indica extract (80.32%) at 0.05 g/mL concentration, while Zanthoxylum zanthoxyloides and Distemonanthus benthamianus had inhibition rates of 71.83% and 61.41%, respectively, at 0.04 g/mL. Tomato plants treated with rice husk extract (0.05 g/mL) had the lowest wilt severity scores of 1.25 and 1.50 for UC 80 and Roma VF varieties, respectively.
Rice husk extract was the most effective treatment against Fusarium wilt in both tomato varieties and could serve as an alternative to synthetic chemicals in controlling Fusarium oxysporum f. sp. lycopersici.
Fungitoxicity of Trichoderma longibrachiatum (Rifai) metabolites against Fusarium oxysporum, Aspergillus niger and Aspergillus tamarii
(Scientific Research Publishing Inc, 2022) Sobowale, A. A.; Uzoma, L. C.; Aduramigba-Modupe, A. O.; Bamkefa, B. A
An experiment was carried out to evaluate the fungitoxic effect of Trichoderma longibrachiatum (Rifai) metabolite on Fusarium oxysporum, Aspergillus niger and Aspergillus tamarii. The fungi were collected from the International Institute of Tropical Agriculture (IITA) and the Nigerian Institute of Science Laboratory Technology (NISLT). Trichoderma longibrachiatum was cultured on one-quarter 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 µm millipore filter disc after centrifugation at 900 rpm for 20 minutes.
Petri plates of each fungus were 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 treated with n-hexane and PDB served as controls. All Petri plates were incubated at 28°C for seven days. Radial and diametric growth of each fungus on all Petri plates were measured daily at 24-hour intervals. Data obtained were analysed using SAS (version 9.3).
Growth inhibition of Fusarium oxysporum, Aspergillus niger and Aspergillus tamarii was significantly higher than in the 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 the control. Generally, inhibition by metabolite extracted with PDB was better than that extracted with n-hexane. Growth inhibition at all concentrations of the metabolite was significantly greater than in the control (P ≤ 0.05). Generally, inhibition at 100%, 50% and 25% concentrations was better than that at 10% concentration of the metabolite.
Trichoderma longibrachiatum metabolite can therefore be said to possess promising fungitoxic potential even at concentrations as low as 25%. Both PDB and n-hexane are effective extraction media for the metabolite.
Fungitoxic Potentials of Ocimum gratissimum L. and Zingiber offcinale (L.) Roscoe Extracts against fungi associated with postharvest rot of Carica papaya L
(Society for Science Education, 2022) Sobowale, A. A.; Agbane, J.; Bamkefa, B. A.; Aduramigba-Modupe, A. O.
The fungitoxic potentials of Ocimum gratissimum and Zingiber officinale extracts on fungi associated with rotting Carica papaya were investigated. Rotting and healthy pawpaw fruits of Carica papaya were obtained from Bodija Market, Ibadan, Nigeria. Isolation of fungi from the rotting fruits was carried out using standard procedures. Pure cultures of the isolated fungi were obtained on Acidified Potato Dextrose Agar (APDA). Leaves of Ocimum gratissimum and rhizomes of Zingiber officinale were obtained from the Botanical Garden, University of Ibadan, Nigeria.
Crude extracts (aqueous and methanol) of the plants were obtained using standard procedures. The antimicrobial potentials of the extracts on the isolated fungi in vitro at concentrations of 25%, 50%, 75% and 100% were evaluated. Their interactive effects on the pathogens were also assessed. Cultures with 0% methanol and water served as controls. All experiments were conducted in triplicates. Petri plates were incubated at room temperature for seven days. Radial and diametric growth of the fungi was measured every 24 hours using a metre rule. Data obtained were subjected to analysis using SAS (version 9.2), and means were separated using Duncan Multiple Range Test (DMRT) at p ≤ 0.05.
The isolated fungi were Colletotrichum gloeosporioides, Lasiodiplodia theobromae and Aspergillus flavus. Inhibitory effects of extracts from both plants and both solvents on the isolated pathogens were significantly better than the control. The inhibitory effect of the methanol extracts was greater than that of the aqueous extracts. The inhibitory effect of Ocimum gratissimum extract was also significantly greater than that of Zingiber officinale (p ≤ 0.05). Inhibition at all extract concentrations was significantly better than the control. However, inhibition at 100% and 75% concentrations was higher than at other concentrations. Inhibition obtained with the different treatment combinations was greater than that achieved with individual concentrations.
Generally, inhibition of Lasiodiplodia theobromae was significantly greater than that of Aspergillus flavus, which in turn was significantly greater than that of Colletotrichum gloeosporioides (p ≤ 0.05). Ocimum gratissimum and Zingiber officinale could therefore be said to possess promising fungitoxic potentials. More work is required to ascertain their efficacy under in vivo conditions.
Antifungal potential of endophytic Bacillus species isolated from tomato (Solanum lycopersicum) against Fusarium oxysporum collected from selected farms in Nigeria
(Taylor and Francis, 2023) Adedire, O. M.; Aduramigba-Modupe, A. O.; Odeniyi, A. O.
Fusarium wilt, caused by Fusarium oxysporum, is a prevalent and destructive disease of tomato (Solanum lycopersicum L.) in Nigeria. The development of safe and efficient biocontrol measures is important for the management of the disease. In this study, the incidence of Fusarium wilt of tomato in four agricultural zones of Oyo State was established through purposive sampling, and the abundance and in vitro biocontrol potential of Bacillus endophytes were determined.
Strains of Fusarium oxysporum and Bacillus endophytes were isolated from tomato plants collected from 21 farms. The in vitro inhibition potential of endophytes was determined through a modified dual-culture assay involving six endophytes and carbendazim (fungicide), arranged in a completely randomized design. Using a disease rating scale of 0–9, the highest wilt severity (6.67) and incidence (39.30%) were observed on Akinware Farm in the Ibadan/Ibarapa agricultural zone of Oyo State. Fusarium oxysporum IB3q caused severe wilt symptoms, including leaf chlorosis, necrosis, vascular discoloration and wilting, on infected Alausa and Ibadan-local tomato varieties.
Thirty-nine strains of Bacillus endophytes were isolated from the tissues of healthy tomato plants. Six of the isolated Bacillus endophytes inhibited Fusarium oxysporum. Bacillus amyloliquefaciens Sa08 and Bacillus subtilis Og04 produced inhibition zones of 15.67 mm and 19.43 mm, respectively, against Fusarium oxysporum and caused hyphal disintegration of the pathogen. These isolates produced cell wall-degrading enzymes with relative activities ranging from 0.87 to 5.04.
Based on their in vitro inhibitory potential, Bacillus amyloliquefaciens Sa08 and Bacillus subtilis Og04 should be considered as prospective biocontrol agents against seed-borne Fusarium pathogens and Fusarium wilt of tomato.
Performance of testers with contrasting provitamin A content to evaluate provitamin A maize for resistance to Aspergillus flavus infection and aflatoxin production.
(Frontiers Media SA, 2023) Mboup, M.; Aduramigba-Modupe, A. O.; Maazou, A.; Olasanmi, B.; Mengesha, W.; Meseka, S.; Dieng, I.; Bandyopadhyay, R.; Menkir, A
This study evaluated the performance of maize testers with contrasting provitamin A (PVA) content for assessing resistance of PVA maize genotypes to Aspergillus flavus infection and aflatoxin accumulation. The objective was to identify superior parental lines and tester combinations that could be used in breeding programs to develop maize hybrids with enhanced provitamin A content and reduced susceptibility to aflatoxin contamination.
The results demonstrated that the choice of tester significantly influenced the identification and selection of maize lines with desirable traits. Some tester combinations were more effective in discriminating among genotypes for resistance to Aspergillus flavus infection and aflatoxin production, while simultaneously maintaining high provitamin A levels. The study identified promising maize lines that can serve as parents in hybrid development programmes aimed at improving nutritional quality and food safety.
Overall, the findings highlight the importance of selecting appropriate testers in maize breeding programmes to facilitate the development of maize varieties that contribute to reducing aflatoxin contamination and combating vitamin A deficiency (VAD) in populations that rely heavily on maize as a staple food.