Atividade antifúngica de óleos essenciais sobre Colletotrichum gloeosporioides e Botrytis cinerea

Abstract

Aromatic plants are bioactive compounds capable of being used as medicines, anti-inflammatory, antimicrobial and others. Essential oils (EO) can be an alternative control option, with the advantage of not contaminating the environment, in addition to offering less risk to animal and human health. The pathogen Colletotrichum gloeosporioides has a wide distribution worldwide and high destructive capacity, feeding among the ten main causes of diseases in cultures of great economic expression. In Brazil, there are 59 species of this fungus that cause disease such as anthracnose in crops such as cereals, vegetables and perennial crops. Botrytis cinerea is responsible for causing gray mold, both pre and post harvest. In Brazil, the fungus causes damage in several plant parts such as branches, flowers and fruits in different cultures such as strawberries, grapes, apples, pepper and ornamentals. The objective is to evaluate the effect of EOs of Lippia alba (erva-cidreira-brasileira), Croton growioides (canelinha), Croton tetradenius (velandinho), Varronia curassavica (erva-baleeira) and Ocimum basilicum (basil or manjericão) on growth, in vitro, of necrotrophic phytopathogenic fungi (C. gloeosporioides and B. cinerea). The experiment was conducted in a completely randomized design, testing four doses (1, 10, 50 and 100 mg/L), 32 treatments for C. gloeosporioides and 30 for B. cinerea, an additional control and a standard fungicide (Score Flexi® Propiconazole + Difeconazole - Syngenta) in four replications. Mycelium of 0.5 cm were defeated in Petri dishes, in contact with EO. The diameters were measured in diametrically opposite separation, obtaining the averages and percentages of inhibition. Thus, they were decomposed to analysis of variance and comparison of means by the Tukey test at 5%, in R-Project®. Using L. alba and O. basilicum EO (access Red Rubin, Dark Opal, Edwinia), 40 to 50% inhibition of fungal growth was obtained in both tested pathogens. Among the tested basil accessions, Dark Opal and Elidia, and V. curassavica inhibited about 50% of the growth of B. cinerea. Thus, oils with higher percentages of inhibition can be alternatives in the control of anthracnose and gray mold in several crops.