The objective of this study was to evaluate the efficacy of plant extracts in managing late blight disease in tomato, in vitro . Crude extracts were from Plectranthus barbatus , Tephrosia vogelii , Sphaeranthus suaveolens and Lantana camara . These were compared with commercial formulations Otiva fungicide and untreated as negative control. Their effectiveness was determined by measuring the inhibition zone of the mycelial growth of the pathogen recorded in triplicate at 48 hours and 72 hours. The results showed significant differences (P ≤ 0.001) among the extracting solvents on percentage inhibition of Phytophthora infestans . Methanol was superior in inhibiting the growth of mycelial growth of P. infestans as compared with ethyl acetate. Furthermore, all plants tested showed antifungal activity against P. infestans . The P. barbatus , L. camara and S. suaveolens were comparable with the commercial fungicide in inhibiting the growth of P. infestans . In this study, T. vogelii extract showed poor results in inhibiting the mycelial growth of P. infestans as compared with other plant extracts. Also, it was observed that, there were significant (P < 0.05) interactive effects between solvent and plant extracts and between incubation time and plant extracts.
Wachira, M.J., Mshenga, M.P. and Saidi, M. (2014) Comparison of Profitability of Small Scalegreen House and Open-Field Tomato Production Systems in Nakuru—North District, Kenya. Asian Journal of Agricultural Sciences, 6, 54-61. https://doi.org/10.19026/ajas.6.5303
Bhowmik, D., Kumar, K.S., Paswan, S. and Srivastava, S. (2012) Tomato—A Natural Medicine and Its Health Benefits. Journal of Pharmacognosy and Phytochemistry, 1, 33-43.
Lima, J.E., Carvalho, R.F., Neto, A.T., Figueira, A. and Peres, L.E. (2004) Micro-MsK: A Tomato Genotype with Miniature Size, Short Life Cycle, and Improved in Vitro Shoot Regeneration. Plant Science, 167, 753-757. https://doi.org/10.1016/j.plantsci.2004.05.023
Maerere, A.P., Sibuga, K.P., Bulali, J.E.M., Mwatawala, M.W., Kovach, J., Kamanywa, S., Mtui, H.D. and Erbaugh, M. (2010) Deriving Appropriate Pest Management Technologies for Smallholder Tomato (Solanum lycoperscum Mill.) Growers: A Case Study of Morogoro, Tanzania. Journal Animal and Plant Science, 6, 663-676.
Maji, S. and Chakrabartty, P.K. (2014) Biocontrol of Bacterial Wilt of Tomato Caused by Ralstonia solanacearum by Isolates of Plant Growth Promoting Rhizobacteria. Australian Journal of Crop Science, 8, 208-214.
Kamoun, S., Furzer, O., Jones, J.D., Judelson, H.S., Ali, G.S., Dalio, R.J., Panabières, F., et al. (2015) The Top 10 Oomycete Pathogens in Molecular Plant Pathology. Molecular Plant Pathology, 16, 413-434. https://doi.org/10.1111/mpp.12190
Sunter, G., Sunter, J.L. and Bisaro, D.M. (2001) Plants Expressing Tomato Golden Mosaic Virus AL2 or Beet Curly Top Virus L2 Transgenes Show Enhanced Susceptibility to Infection by DNA and RNA Viruses. Virology, 285, 59-70. https://doi.org/10.1006/viro.2001.0950
Kankam, F. and Adomako, J. (2014) Influence of Inoculum Levels of Root Knot Nematodes (Meloidogyne spp.) on Tomato (Solanum lycopersicum L.). Asian Journal of Agriculture and Food Science, 2, 171-178.
Fontem, D.A., Olanya, O.M., Tsopmbeng, G.R. and Owona, M.A.P. (2005) Pathogenicity and Metalaxyl Sensitivity of Phytophthora infestans Isolates Obtained from Garden Huckleberry, Potato and Tomato in Cameroon. Crop Protection, 24, 449-456. https://doi.org/10.1016/j.cropro.2004.09.012
Nowicki, M., Foolad, M.M.R., Nowakowska, M. and Kozik, E.U.E. (2012) Potato and Tomato Late Blight Caused by Phytophthora infestans: An Overview of Pathology and Resistance Breeding. Plant Disease, 96, 4-17. https://doi.org/10.1094/PDIS-05-11-0458
Agrios, G.N. (2005) Plant Pathology. 5th Edition, Academic Press, London, New York, 922 p.
Mizubuti, E.S., Júnior, V.L. and Forbes, G.A. (2007) Management of Late Blight with Alternative Products. Pest Technology, 1, 106-116.
Goufo, P., Fontem, A. and Ngnokam, D. (2010) Evaluation of Plant Extracts for Tomato Late Blight in Cameroon. New Zealand Journal of Crop and Horticultural Science, 38, 171-176.
Gullino, M.L., Leroux, P. and Smith, C.M. (2000) Uses and Challenges of Novel Compounds for Plant Disease Control. Crop Protection, 19, 1-11. https://doi.org/10.1016/S0261-2194(99)00095-2
Geraldin, L.W.M. (2016) Efficacy of Plant Extracts and Antagonistic Fungi as Alternatives to Synthetic Pesticides in Management of Tomato Pests and Diseases. Doctoral Dissertation, University of Nairobi, Nairobi, Kenya.
Goufo, P., Mofor, T.C., Fontem, D.A. and Ngnokam, D. (2008) High Efficacy of Extracts of Cameroon Plants against Tomato Late Blight Disease. Agronomy for Sustainable Development, 28, 567-573. https://doi.org/10.1051/agro:2008036
Kimani, V. (2014) Bio-Pesticides Development, Use and Regulation in Kenya. Regional Experts Workshop on Development, Regulation and Use of Bio-Pesticides in East Africa, Nairobi, Kenya, 22-23 May 2014.
Judelson, H.S. and Tooley, P.W. (2000) Enhanced Polymerase Chain Reaction Methods for Detecting and Quantifying Phytophthora infestans in Plants. Phytopathology, 90, 1112-1119. https://doi.org/10.1094/PHYTO.2000.90.10.1112
Musila, F.M., Nguta, J.M., Lukhoba, C.W. and Dossaji, S.F. (2017) Antibacterial and Antifungal Activities of 10 Kenyan Plectranthus Species in the Coleus clade. Journal of Pharmacy Research, 11, 1003-1014.
Mahajan, N.G., Chopda, M.Z. and Mahajan, R.T. (2015) A Review on Sphaeranthus indicus Linn: Multipotential Medicinal Plant. International Journal of Pharmaceutical Research and Allied Sciences, 4, 48-74.
Saikia, A.K. and Sahoo, R.K. (2011) Chemical Composition and Antibacterial Activity of Essential Oil of Lantana camara L. Journal of Scientific Research, 8, 599-602.
Al-Samarrai, G.F., Singh, H. and Syarhabil, M. (2013) Extracts Some Plants on Controlling Green Mold of Orange and on Postharvest Quality Parameters. World Applied Sciences Journal, 22, 564-570.
Al-Samarrai, G., Singh, H. and Syarhabil, M. (2012) Evaluating Eco-Friendly Botanicals (Natural Plant Extracts) as Alternatives to Synthetic Fungicides. Annals of Agricultural and Environmental Medicine. 19, 673-676.
Odhiambo, A.J., Siboe, G.M., Lukhoba, C.W. and Dossaji, F.S. (2009) Antifungal Activity of Crude Extracts of Selected Medicinal Plants Used in Combination in Lake Victoria Basin, Kenya. Plant Product Research Journal, 13, 35-43.
Javaid, A. and Rehman, A.H. (2011) Antifungal Activity of Leaf Extracts of Some Medicinal Trees against Macrophomina phaseolina. Journal of Medical Plants Research, 5, 2858-2872.
Mahlo, S.M., Chauke, H.R., McGaw, L.J. and Eloff, J.N. (2013) Antioxidant and Antifungal Activity of Selected Plant Species Used in Traditional Medicine. Journal of Medicinal Plants Research, 7, 2444-2450.
Bandar, H., Hijazi, A., Rammal, H., Hachem, A., Saad, Z. and Badran, B. (2013) Techniques for the Extraction of Bioactive Compounds from Lebanese Urtica dioica. American Journal of Phytomedicine and Clinical Therapeutics, 1, 507-513.
Vashist, H. and Jindal, A. (2012) Antimicrobial Activities of Medicinal Plants—Review. International Journal of Research in Pharmaceutical and Biomedical Sciences, 3, 222-230.
Azwanida, N.N. (2015) A Review on the Extraction Methods Use in Medicinal Plants, Principle, Strength and Limitation. Medicinal and Aromatic Plants, 4, 196.
Ndakidemi, P.A. and Dakora, F.D. (2003) Legume Seed Flavonoids and Nitrogenous Metabolites as Signals and Protectants in Early Seedling Development. Functional Plant Biology, 30, 729-745. https://doi.org/10.1071/FP03042
Makoi, J.H.R. and Ndakidemi, P.A. (2007) Biological, Ecological and Agronomic Significance of Plant Phenolic Compounds in Rhizosphere of the Symbiotic Legumes. African Journal of Biotechnology, 6, 1358-1368.
Hubert, G.Y.J., Julienne, N., Charles, D.D., Daniel, F., Sandrine, P.T., Romain, F.F. and Henry, A.Z.P. (2013) Antifungal Potential and Phytochemical Analysis of Extracts from Seven Cameroonian Plants against Late Blight Pathogen Phytophthora infestans. International Journal of Current Microbiology and Applied Sciences, 2, 140-154.
Mpumi, N., Mtei, K., Machunda, R. and Ndakidemi, P.A. (2016) The Toxicity, Persistence and Mode of Actions of Selected Botanical Pesticides in Africa against Insect Pests in Common Beans, P. vulgaris: A Review. American Journal of Plant Sciences, 7, 138-151. https://doi.org/10.4236/ajps.2016.71015