Caracterização e sensibilidade de Colletotrichum spp. isolado de Vitis labrusca a óleos essenciais

Abstract

Viticulture is an activity of economic and social importance, with grapes being the fourth most produced fruit in Brazil. Between 2016 and 2021, there were reductions in cultivated areas and grape productivity. Climatic adversities, the occurrence of diseases and the difficulty in controlling these constitute obstacles to its production. Among the diseases that affect the crop, anthracnose and ripe grape rot are important diseases, because in addition to being destructive, they affect several vine cultivars. They are responsible for causing damage to production, significantly reducing the quality and quantity of fruits. Anthracnose is reported to be caused by the fungus Elsinoe ampelina, and ripe grape rot is associated with Glomerella cingulata. However, recent studies point to Colletotrichum species as causal agents of both diseases. Control occurs basically by fungicides, and their continuous and non-rational use can promote the selection of resistant genotypes of the pathogen. In this way, new alternatives are studied to control phytopathogens that add to conventional methods, such as the use of essential oils and their major compounds. There are indications that they are efficient in preventing the development of resistant populations of pathogens and pests. This study aimed to characterize the causal agents of grapevine anthracnose collected in Mato Grosso do Sul, Paraná, Santa Catarina, and the Rio Grande do Sul. In addition, to evaluate their sensitivity to clove (Syzygium aromaticum [L] Merr. et Perry), cinnamon (Cinnamomum cassia Presl), and eucalyptus (Eucalyptus globulus Labill) essential oils and their major compounds, eugenol, cinnamaldehyde, and eucalyptol, respectively. Cultural and morphological characterization of Colletotrichum spp. isolates, pathogenicity test on leaves and fruits, and evaluation of the antifungal activity of the oils and compounds mentioned on the isolates were carried out in vitro. According to the cultural characteristics found in the isolates from different geographic origins, the cultural and morphological characterization patterns suggest that they may belong to the complexes of C. gloeosporioides, C. acutatum and Elsinoe ampelina. The substances tested effectively controlled Colletotrichum spp., and the results indicate that they exerted fungistatic and fungicidal effects. Each essential oil and its compound showed a different behavior than the isolates, which may be related to its composition. The results suggest that they can be explored as an alternative treatment and in developing new products to control anthracnose and ripe grape rot in the field.