Characterization and in vitro Biocontrol of the Agent Responsible for Dry Rot of Tomato Using Biopesticides Based on Bacillus thuringiensis and Plant Extracts
Alahou André Gabaze GADJI *
Programme Cultures Maraîchères et Protéagineuses, Station de Recherche sur les Cultures Vivrières de Bouaké, Centre National de Recherche Agronomique (CNRA), 01 BP 633 Bouaké 01, Côte d’Ivoire.
Claude Ghislaine KOUADJO
Laboratoire Central de Biotechnologie, Centre National de Recherche Agronomique (CNRA), 01 BP 1740 Abidjan 01, Côte d’Ivoire.
Gaston Koffi KOUAME
UFR de Sciences Biologiques, Université Peleforo Gon Coulibaly, BP 1328 Korhogo, Côte d’Ivoire.
Pulchérie N’Guessan Kan KOUAKOU
Programme Cultures Maraîchères et Protéagineuses, Station de Recherche sur les Cultures Vivrières de Bouaké, Centre National de Recherche Agronomique (CNRA), 01 BP 633 Bouaké 01, Côte d’Ivoire.
Christian-Landry Ossey
Programme Cultures Maraîchères et Protéagineuses, Station de Recherche sur les Cultures Vivrières de Bouaké, Centre National de Recherche Agronomique (CNRA), 01 BP 633 Bouaké 01, Côte d’Ivoire.
Aya Félicité N’Gaza
Programme Cultures Maraîchères et Protéagineuses, Station de Recherche sur les Cultures Vivrières de Bouaké, Centre National de Recherche Agronomique (CNRA), 01 BP 633 Bouaké 01, Côte d’Ivoire.
Noupé Diakaria COULIBALY
Programme Cultures Maraîchères et Protéagineuses, Station de Recherche sur les Cultures Vivrières de Bouaké, Centre National de Recherche Agronomique (CNRA), 01 BP 633 Bouaké 01, Côte d’Ivoire.
Lassina FONDIO
Programme Cultures Maraîchères et Protéagineuses, Station de Recherche sur les Cultures Vivrières de Bouaké, Centre National de Recherche Agronomique (CNRA), 01 BP 633 Bouaké 01, Côte d’Ivoire.
Kouabenan ABO
Unité de Recherche Biologie et Santé des Plantes, Unité Mixte de Recherche et d’Innovation Sciences Agronomiques et Procédés de Transformation (UMRI-SAPT), Institut National Polytechnique Félix Houphouët-Boigny (INP-HB), BP 1093 Yamoussoukro, Côte d’Ivoire.
*Author to whom correspondence should be addressed.
Abstract
Aims: This study was aimed to characterize the fungal agent associated with dry rot and to evaluate in vitro the antifungal activity of biopesticides based on Bacillus thuringiensis var. kurstaki HD-1 (Btk HD-1) and plant extracts against this pathogen.
Study Design: During the in vitro efficacy testing, the Petri dishes were arranged in completely randomized blocks.
Place and Duration of Study: Food Crop Research Station in Bouaké, Biotechnology Laboratory in Abidjan (CNRA), and in the Didiévi, Kongoue-Kouadiokro and Subiakro localities in central Côte d'Ivoire, between August 2022 and June 2023.
Methodology: Organs (stems, leaves, and fruits) of symptomatics tomato plants were sampled for the isolation and identification of the pathogen. Efficacy tests were performed on PDA culture medium supplemented with biopesticides based on Btk HD-1, aqueous extracts of garlic, neem and carapa oils, and the chemical fungicide mancozeb 80 WP at varying concentrations.
Results: The results obtained implicated Lasiodiplodia theobromae as a potential agent of damage observed in tomato crops in the localities of Didiévi, Kongoue-Kouadiokro, and Subiakro, in central Côte d'Ivoire. The average rate of inhibition of mycelial growth of the fungus was not significantly different (P = 1.00) between the concentrated aqueous garlic extract at 0.2 g/l and mancozeb (5 g/l). However, this rate varied according to the treatments and concentrations applied. Thus, neem and carapa oils, and Btk HD-1 induced average inhibition rates of 42.01%, 72.57%, and 49.17%, respectively. Significant differences (P ˂ 0.05) were observed between these different treatments and mancozeb (chemical fungicide).
Conclusion: Aqueous garlic extract could be used in integrated pest management programs against this fungus in tomato cultivation to limit production losses and ensure the sustainability of this crop.
Keywords: Biopesticides, Lasiodiplodia theobromae, mancozeb 80 WP, tomato cultivation, efficacy test, Côte d’Ivoire