Atividade antifúngica e proteção do tomateiro por extratos de plantas medicinais

Abstract

The present work aimed to evaluate, in vitro, the fungitoxicity of aqueous crude extracts (ACEs) of Achillea millefolium, Artemisia camphorata, Cymbopogon citratus and Rosmarinus officinalis to Alternaria solani and their protective effect on tomato plants under greenhouse conditions. To evaluate the antifungal activity of ACEs, they were incorporated into potato-dextrose-agar medium and the inhibition of mycelial growth, sporulation and conidia germination was evaluated. The protective effect in plants was evaluated by means of preventive spraying (72 hours before inoculation) with ACE, at concentrations of 10 and 20%, in the first two leaves. Disease severity was verified 15 days after inoculation. It was observed that ACEs did not inhibit mycelial growth, but they had significant effects on the reduction of germination and sporulation, especially the ACEs of A. camphorata, C. citratus and R. officinalis, at concentrations up to 20%. A reduction was observed in the number of lesions in relation to the control, in leaves above those treated, observing the systemic effect of the extracts. The extracts from the studied plants may be promising in the control of early blight on tomato plants. Copyright by the Brazilian Phytopathological Society.