Uso de extrato de canela, extrato de cravo e hipoclorito de sódio no controle de Fusarium oxysporum f. sp. lycopersici e Alternaria alternata

Abstract

The tomato crop is very sensitive to phytosanitary problems, among the fungal diseases that affect the crop, the Fusarium wilt caused by Fusarium oxysporum f. sp. lycopersici and the black spot, caused by Alternaria alternata. The use of pesticides is one of the main ways to manage pests and diseases in tomato crops, making control measures based on systematic applications of fungicides following a calendar of weekly applications. While the application of fungicides brings benefits to the productivity of horticultural crops, their use has been restricted by environmental risks and the greater demand for food without the presence of residues of these substances. In this context, the use of natural products from plants and already used as food can be an alternative form of control. Thus, this work aims to evaluate the in vitro growth inhibition potential of different pathogenic races of Fusarium oxysporum f. sp. lycopersici (causer of fusarium wilt) and Alternaria alternata (black spot), by the use of aqueous extract of cinnamon and aqueous extract of clove, in addition to the use of sodium hypochlorite solution, as well as its application to reduce symptoms of black pinta on tomato fruits in post-harvest. For this purpose, the work was divided into two chapters, where in vitro tests were performed in the first chapter to observe the potential of the aqueous extract of cinnamon and sodium hypochlorite in the control of Alternaria alternata and the three main races of Fusarium oxysporum f. sp. Lycopersici. In the second chapter, the effects of the aqueous extract of cinnamon and the aqueous extract of clove on the control of Alternaria alternata in vitro and post-harvest of tomatoes were treated. Complete growth inhibition of the three races of Fusarium oxysporum f. sp. lycopersici and Alternaria Alternata only when using sodium hypochlorite from a concentration of 3%, and a partial inhibition with the use of cinnamon extract. Both, cinnamon extract and sodium hypochlorite solution, at concentrations above 2%, reduced IVCM values. Total inhibition of Alternaria mycelial growth under in vitro conditions was obtained using 5% clove extract. The combination of cinnamon and clove, both at 2.5 and 5%, also enabled complete inhibition of mycelial growth. In addition to the effect on mycelial growth, it was also possible to verify the inhibition of spore germination and control of the fungus in the post-harvest of tomato fruits.