Cinnamon and clove aqueous extracts promote in vitro and postharvest control of Alternaria alternata in tomato fruit
摘要
Post-harvest fungal diseases are a leading cause of food losses. In tomato cultivation, different species of Alternaria sp. are known to cause necrotic spots and fruit softening, which ultimately reduce both productivity and quality. Spraying synthetic fungicides is the primary method to control this disease. Alternative methods such as the products derived from the secondary metabolism of plants are emerging as viable natural pesticide options for agricultural use. Their use can increase the safety and quality of fresh foods, especially vegetables and fruits. Therefore, this study aimed to evaluate the effectiveness and the mode of action of aqueous extracts of cinnamon and clove and their main active ingredients (cinnamaldehyde and eugenol) in the in vitro and in vivo post-harvest control of A. alternata in tomato fruit. The total inhibition of mycelial growth and spore germination in vitro of A. alternata was achieved by using clove aqueous extract at 5% or the mixture of cinnamon and clove, at 2.5 or 5% concentration. The main antifungal activity of these extracts against A. alternata was attributed to the clove (eugenol). However, the in vitro anti-fungal activity was observed both for eugenol and cinnamaldehyde when these specific metabolites were applied in the culture medium. The use of botanical fungicides such as clove or the clove and cinnamon extracts can effectively control the post-harvest Alternaria disease in tomatoes, diminishing the use of synthetic pesticides and increasing food safety.