Antifungal Activity of Citrus Limon Leaf Extracts against Fungal Pathogens Isolated from Decaying Potato Tubers in Supermarkets of the Eastern Cape Province, South Africa

John Meomikem Ehiobu


Globally, fungal pathogens pose severe threats to stored cereal and tuber crops, resulting in substantial losses in economic crops. This study investigated the inhibitory activities of aqueous, ethanol, and acetone leaf extracts of Citrus limon L. Osbeck against the mycelial growth of Curvularia mebaldsii, Fusarium oxysporum, and Penicillium species isolated from spoilt potato tubers retailed within supermarkets in Eastern Cape Province, South Africa. Various concentrations (100 g/L, 50 g/L, and 25 g/L) of the C. limon leaf extracts (aqueous, acetone and ethanol) were prepared and (5 mL) amended with potato dextrose agar (oxoid, UK) previously inoculated with the 7-day old culture of each fungal isolates before incubation at 28 oC. The percentage growth inhibition was determined to evaluate the antifungal efficacy of each extract. Aqueous, ethanol and acetone extracts at 50g/L and 100 g/L displayed 100 % inhibition against all three pathogens except Penicillium sp. with 91.0 - 90.97 % inhibition. The ethanol and acetone extracts had the most inhibitory effects against F. oxysporum C. mebaldsii. In contrast, the aqueous extracts displayed the least effects, though not significantly different (p<0.05) across the concentrations. The notable antifungal effects against F. oxysporum, a prominent pathogen of post-harvest spoilage of potatoes, suggest the potential use of C. limon extracts to enhance the shelf-life of potatoes in supermarkets, specifically, and for post-harvest storage in general.


Biofungicides; Incubation; Inhibitory activity; Pathogenicity; Plant extracts.

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Alara, O.R., Abdurahman, N.H., Ukaegbu, C.I., Kabbashi, N.A., 2019. Extraction and characterization of bioactive compounds in Vernonia amygdalina leaf ethanolic extract comparing Soxhlet and microwave-assisted extraction techniques. Journal of Taibah University for Science 13, 414-422.

Ameida, F., Rodrigues, M.L., Coelho, C., 2019. The still understanding problem of fungal diseases worldwide. Frontiers in Microbiology 10, 1-5.

Askane, L., Talib, I., Boubaer, H., Boubaker, H., Boudyach, E.H., 2012. In vitro and in vivo antifungal activity of several Moroccan plants against Penicillium italicum, the causal agent of Citrus blue mold. Crop Protection 40, 53-58.

Asker, M., Elgengaihi, S.E., Hassan, E.M., Mohammed, M.A., Arafa, M.M., 2020. Phytochemical constituents and antibacterial activity of Citrus lemon leaves. Bulletin of the National Research Centre 44, 194.

Balestrini, R., Ghiagnone, S., Quiroga, G., Fiorilli, V., Romano, I., Gambino, G., 2020. Long term impact of chemical and alternative fungicides applied to grape vine CV Nebbiolo on berry transcriptome. International Journal of Molecular Sciences 21, 1-18.

Barnett, H.L., Hunter, B.B., 1972. Illustrated genera of imperfect fungi. Burgess publishing company. Minneapolis, Minneapolis, Minnessota, USA 90-241.

Burgos, G., Zum, Felde T., Andre, C., Kubow, S., 2020. The potato and its contribution to the human diet and health. The potato crop: Its agricultural, nutritional and social contribution to humankind, pp. 37-74.

Chandrasekara ,A., Kumar, T.J., 2016. Roots and tuber crops as functional foods: a review on phytochemical constituents and their potential health benefits. International Journal of Food Science 2016, 3631647.

Egbuta, M.A., Mwanza, M., Babalola, O.O., 2017. Health risks associated with exposure to filamentous fungi. International Journal of Environmental Research and Public Health 14, 719.

Ehiobu, J., Idamokoro, E.M., Afolayan, A.J., 2020. Potato rot disease incidence among supermarket owners within the Raymond Mhlaba local municipality of South Africa. AIMS Agriculture and Food 52, 181-189.

Ehiobu, J., Idamokoro, E.M., Afolayan, A.J., 2021. Phytochemical content and antioxidant potential of leaf extracts of Citrus limon L. Osbeck collected in the Eastern Cape Province South Africa. South African Journal of Botany 1411, 480-486.

Ehiobu, J.M., Ogu, G.I., 2016. In vitro effect of Colocasia esculenta l. leaf extracts on mycelial growth and spore germination of Fusarium species. International Journal of Health Sciencs and Research 1, 47-52.

Ehiobu, J.M., Ogu, G.I., 2018. Phytochemical content and in vitro anti-mycelial efficacy of Colocasia esculenta L, Manihot esculenta Crantz and Dioscorea rotundata Poir leaf extracts on Aspergillus niger and Botryodiplodia theobromae. Journal of Horticulture and Plant Research 1, 9-18.

Erasto, P., Mbwambu, H., Nondo, R.S.O., Lall, N., Lubschagne, A., 2011. Actimycobacterial antioxidant activity and toxicity of extracts from the root of Rauvolfia vomitoria R. caffra. ScopeMed 1, 73-80.

Ezeonu, C.S., Imo, C., Agwaranze, D., Iruka, A., Joseph, A., 2018. Antifungal effect of aqueous and ethanolic extracts of neem leaves, stem, bark and seeds on fungal rot diseases of yam and cocoyam. Chemistry and Biology 5, 1-9.

Giwa, V.I., Akombo, A., 2016. Studies on the antimicrobial potency of five crude plants and chemical fungicides in in vitro control of Aspergillus flavus causal agents of White yam Dioscorea alata tuber rot. Journal of Plant Science and Research 1, 1-8.

Gwa, V.I., Richard, I.B., 2018. Susceptibility of white yam Dioscorea rotundata Poir tuber to rot fungi and control with extracts of Zingiber officinale Rosc. Azadirachta Indica A. Juss. and Piper guineense Schumach. Journal of Plant Pathology and Microbiology 9, 452.

Gyasi, E., Akrofi, S., Adongo, B.A., Osafo, E.A., Kotey, D.A., Mohammed, A., 2022. Fungi associated with sweet potato tuber rot at CSIR - PGRRI Bunso Eastern Region, Ghana. Ghana Journal of Agricultural Science 57(1), 106-112.

Heltoft, P., Molteberg, E.L., Nastad, R., Hermansen, A., 2015. Effect of maturity level and potato cultivar on development of Fusarium dry rot in Norway. Potato Research 58, 205-219.

Hiruma, K., 2019. Roles of plant-derived secondary metabolites during interaction with pathogenic and beneficial microbes under conditions of environmental stress. Microorganisms 7, 1-9.

Huang, J., Rucker, A., Schmidt, A., Gleixner, G., Gershenzon, J., Trumbore, S., Hartmann, H., 2020. Production of constitutive and induced secondary metabolites in a coordination with growth and storage in Norway spruce saplings. Tree Physiology 40, 928-942.

Ibrahim, M., Shehu, K., Sambo, S., Tukur, I.A., Tafinta, I.Y., 2014. Identification of fungi associated with storage rots of Irish Potato Solanum tuberosum L. tubers in Sokoto Metropolis. Annals of Biological Sciences 2, 1-4.

Ikechi-Nwogu, C.G., Nworuka, N., 2023. Isolation and identification of common fungal pathogens invading sweet potatoes Ipomoea batatas sold in Choba market port Harcourt Nigeria. Journal of Applied Sciences and Environmental Management 27, e2717.

Iqbal, U., Mukhtar, T., 2020. Inhibitory effects of some fungicides against Macrophomina phaseolina causing charcoal rot. Pakistan Journal of Zoology 52(2), 709-715.

Iqbal, U., Mukhtar, T., Iqbal, S.M., 2014. In vitro and in vivo evaluation of antifungal activities of some antagonistic plants against charcoal rot causing fungus, Macrophomina phaseolina. Pakistan Journal of Agricultural Sciences 51 (3), 689-694.

Jennings, S.A., Kochler, A., Nicklin, K.J., Deva, C., Salt, S.M., Challinor, A.J., 2020. Global potato yields increase under climate change with adaptation and CO2 fertilization. Frontiers in Food Sustainable Systems 4, 1-17.

Khatoon, A., Mohapatra, A., Satapathy, K.B., 2017. Studies on fungi associated with storage rot of sweet potato [Ipomoea batatas L. Lam.] root tubers in Odisha, India. International Journal of Microbiology and Mycology 5, 1-7.

Lai, J., Liu, T., Liu, B., Kuang, W., Song, S., 2022. First Report of Curvularia plantarum causing leaf spot on sweet potato Ipomoea batatas in China. Plant Disease 106, e1753

Lengai, G.M.W., Muthomi, J.W., Mbega, E.R., 2020. Phytochemical activity and role of botanical pesticides in pest management for sustainable agricultural crop production. Scientific African 7 e00239.

Liu, J., Sun, Z., Zou, Y., Li, W., He, F., Huang, X., Lin, C., Cai, Q., Wisniewski, M., Wu, X., 2021. Pre and post-harvest measures used to control decay and mycotoxigenic fungi in potato Solanum tuberosum L. during storage. Critical Review in Food Science and Nutrition 62, 415-428.

Liu, N., Zao, R., Qlao, L., Zhang, Y., Li, M., Sun, H., Zing, Z., Wang, X., 2020. Growth stages, classification of potato crop based on analysis of optimization. Sensors 10, 20.

Madrid, H., Cunha, KC, Da., Gené, J., Cano, J., Sutton, D.A., Guarro, J., Crous, P.W., 2014. Novel Curvularia species from clinical specimens. Persoonia 33, 48-60.

Makni, M., Jemai, R., Kriaa, W., Chtourou, Y., Fetoui, H., 2018. Citrus limon from Tunisia, phytochemical and physicochemical properties and biological activities. BioMed Research International 2018, e6251546

Marin-Felix, Y., Hernández-Restrepo, M., Crous, P.W., 2020. Multi-locus phylogeny of the Genus Curvularia and description of ten new species. Mycological Progress 19, 559-588.

Musto, M., Potenza, G., Cellini, F., 2014. Inhibition of Penicillium digitatum by a crude extract from Solanum nigrum leaves. Biotechnology Agronomy Society and Environment 18, 174-180.

Nisa, T., Haq, M.I., Mukhtar, T., Khan, M.A., Irshad, G., 2022. Incidence and severity of common scab of potato caused by Streptomyces scabies in Punjab, Pakistan. Pakistan Journal of Botany 54(2), 723-729.

Nsofor, G.C., 2020. Fungal and bacterial pathogens associated with soft rot disease of sweet potato Ipomoea batatas L Lam. Nigeria Agricultural Journal 51, 213-218.

Onukwuorji, C.A., Ramesh, R.P., Okigbo, R.N., 2012. Isolation of fungi causing rot disease of Cocoyam Colocasia esculenta L Schott and control with plants extracts. Global Advanced Research Journal of Agricultural Science C1, 33-47.

Pang, L-J., Adeel, M., Shakoor, N., Guo, K-R., Ma, D-F., Ahmad, M.A., Lu, G-Q., Zhao, M-H., Li, S-E., Rui, Y-K., 2021. Engineered nanomaterials suppress the soft rot disease (Rhizopus stolonifer) and slow down the loss of nutrient in sweet potato. Nanomat 11, 2572.

Paul, N.C, Park, S., Liu, H., Lee, J.G., Han, G.H., Kim, H., Sang, H., 2021. Fungi associated with post-harvest diseases of sweet potato storage roots and in vitro antagonistic assay of Trichoderma harzianum against the diseases. Journal of Fungi Basel 711, 927

Paul, N.C., Park, W., Lee, S., Chung, M.N., Lee, H.U., Yang, J.W., 2020. Occurrence of sweet potato Ipomoea batatas wilt and surface rot disease and determining resistance of selected varieties to the pathogen in Korea. Plants 94, 497.

Perez, W., Forbes, G.A., Arias, R., Pradel, W., Kawarazuka, N., Andrade-Piedra, J., 2022. Farmer perceptions related to potato production and late blight management in two communities in the Peruvian Andes. Frontiers in Sustainable Food Systems 6, 7-14.

Raji, R., Raveendran, K., 2013. Antifungal activity of selected plant extracts against phytopathogenic fungi Aspergillus niger. Asian Journal of Plant Science and Research 3, 13-15.

Ray, H., Hammerschmidt, R., 1998. Responses of potato tuber to infection by Fusarium sambucinum. Phytopathological and Molecular Plant Pathology 53, 82-91.

Sabarwal, A., Kumer, K., Sing, A.P., 2018. Hazardous effects of chemical pesticides on human health cancer and other associated disorders. Environmental Toxicology and Pharmacology Journal 63, 103-114.

Scattolini, A., Hernández, R.L., González, I.H., 2020. Identification of Fusarium oxysporum causing sweet potato rot Ipomoea batatas L and Lamb in Uruguay. Agrociencia 24, 124.

Seepe, H.A., Nxumalo, W., Amoo, S.O., 2021. Natural products from medicinal plants against phytopathogenic Fusarium species: current research endeavours, challenges and prospects. Molecules 26, 6539.

Shahbaz, M., Akram, A., Raja, N.I., Mukhtar, T., Mehak, A., Fatima, N., Ajmal, M., Ali, K., Mustafa, N., Abasi, F. 2023. Antifungal activity of green synthesized selenium nanoparticles and their effect on physiological, biochemical, and antioxidant defense system of mango under mango malformation disease. PLoS ONE 18(2), e0274679.

Shahzaman, S., Inam-ul-Haq, M., Mukhtar, T., Naeem M., 2015. Isolation, identification of antagonistic rhizobacterial strains obtained from chickpea (Cicer arietinum L.) field and their in-vitro evaluation against fungal root pathogens. Pakistan Journal of Botany 47(4), 1553-1558.

Shuping, D.S.S., Eloff, J.N., 2017. The use of plants to protect plants and food against fungal pathogens. African Journal of Traditional, Complementary and Alternative Medicines 14, 120-127.

Singh, R., Gupta, M., Singal, P., Goyal, S., Updhyay, S.K., 2021. In vitro antimicrobial activities of vegetables potato cucumber, sweet potato and ginger peel wastes for eco-friendly microbial management. International Journal of Botany Sciences 6, 134-137.

Sohail, A.A., Bani-Hassan, B.M., 2018. Morphological and molecular identification of fungi isolated from different environmental sources in the Northern Eastern desert of Jordan. Journal of Biological Sciences 11, 329-337.

Stefanczyk, E., Sabkowiak, S., Brylinska, M., Jadwiga, S.J., 2016. Diversity of Fusarium species associated with dry rot disease of potato tubers in Poland. European Journal of Plant Pathology 145, 871-844.

Steglińska, A., Sulyok, M., Janas, R., Grzesik, M., Liszkowska, W., Kręgiel, D., Gutarowska, B., 2023. Metabolite Formation by fungal pathogens of potatoes (Solanum tuberosum L.) in the presence of bioprotective agents. International Journal of Environmental Research and Public Health 20, 5221.

Tijiani, A., Adebitan, S.A., Gurama, A., Aliyu, M., Dawaji, A.Y., Haruna, S.G., Muhammmed, N.A., 2013. Efficacy of some Botanicals for the control of wet rot diseases on mechanically injured sweet potato caused by Rhizopus stolonifer in Bauchi state. International Journal of Scientific and Research Publications 3, 1-10

Tiwari, R.K., Kumar, R., Sharma, S., Sagar, V., Aggarwal, R., Naga, K.C., Lal, M.K., Chourasia, K.N., Kumar, D., Kumar, M., 2020. Potato dry rot disease, current status pathogenomics and management. BioTech 1011, 503.

Tortoe, C., Obodai, M., Amoa-Awua, W., 2019. Microbial deterioration of white variety sweet potato Ipomoea batatas under different storage structures. International Journal of Plant Biology 1, 52-55.

Trabelsi, B.M., Abdallah, R.A.B., Kthiri, H.W., Remadi, M.D., 2016. Assessment of the antifungal activity of non-pathogenic potato-associated fungi towards Fusarium species causing tuber dry rot disease. Journal of Plant Pathology and Microbiology 7, 1-7.

Wharton, P.S., Tumbalam, P., Kirk, W.W., 2006. First report of potato tuber sprout rot caused by Fusarium sambucinum in Michigan. Plant Disease 90, 1460.

Xue, H., Liu, Q., Yang, Z., 2023. Pathogenicity, mycotoxin production, and control of potato dry rot caused by Fusarium spp.: a review. Journal of Fungi 98, 843.

Zaheer, K., Akhtar, M.H., 2016. Potato production, usage, and nutrition-a review. Critical Reviews in Food Science and Nutrition 56, 711-21.

Zanna, H., Tijani, Y., Abubakar, S., Modu, B., Damasak, A.A., Uzairu, S.M., 2021. Fungicidal potential of selected plant extracts against human pathogenic fungi. Scientific African 13, 1-6.

Zaria, A.M.B., 2014. Antifungal activity of extracts from five Egyptian wild medicinal plants against late blight disease of tomato and potato. Pflanzenschutz 47, 1988-200

Zhang, H., Birch, J., Pei, J., Ahmed, I.A.M., Yang, H., Dias, G., Abd El-Aty, A.M., Bekhit, A.E-D., 2019. Identification of six phytochemical compounds from Asparagus officinalis L. root cultivars from New Zealand and China using UAE-SPE-UPLC-MS/MS: effects of extracts on H2O2-induced oxidative stress. Nutrients 11, 1-17.

Zhao, J., Zhang, J., Li, P., Xu, Y., He, Y., Fan, L., 2020. Triterpenoid saponins in tea Camellia senensis plants: biosynthetic gene–expression, content variations chemical identification and cytotoxicity. International Journal of Food Science and Nutrition 72, 308-323.



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