Antifungal activity of botanicals on causal agents of tomato fungal diseases

Abstract

Tomatoes (Lycopersicum esculentum) diseases are among the most constraining factors of tomato production in Côte d’Ivoire. The objective of this study was to evaluate the antifungal activity of Carica papaya and Hydrocotyle bonariensis leaf aqueous extracts, for preventive efficacy against tomatoes diseases agents Alternaria sp., Fusarium sp1 and Fusarium sp2. A greenhouse study was conducted using three different concentrations of leaf extracts (12.5, 25 and 37.5 mg ml-1) obtained by diluting 25, 50 and 75%, respectively, of the crude extract (50 mg ml-1) on the three tomato pathogenic fungi. The concentrations of each of the two extracts with the best fungistatic activities on fungal isolates were selected for in vivo tests. All aqueous extracts inhibited fungal mycelial growth by more than 70%, at the highest concentration (37.5 mg ml^-1); compared to the other two concentrations. At 37.5 mg ml-1, the extracts reduced the severity of fungal diseases on tomato plants compared to the control. Hydrocotyle bonariensis was more effective. A more refined formulation of these extracts could increase their effectiveness and serve for sustainable control of tomato fungal diseases.