Use of Rosmarinus officinalis Essential Oil and its Fractions in the Alternative Control of Grapevine Phytopathogens

Abstract

Abstract Gray rot and grape ripe rot stand out as important vineyard diseases, being caused by the phytopathogens Botrytis cinerea and Colletotrichum acutatum, respectively. Control is usually conducted with synthetic fungicides that can cause problems for human health and the environment. Thus, searching for new alternative disease management methods is necessary, including using essential oil (EO) with fungicidal activity. The present study aimed to evaluate the chemical composition and fungicidal effect of Rosmarinus officinalis EO, as well as its fractions on the mycelial growth and conidial germination of B. cinerea and C. acutatum, in vitro and in vivo. The EO had α-pinene and 1,8-cineole as major compounds. In the vacuum fractional distillation, there was a variation in the chemical composition and the relative quantity of each compound according to the fraction analyzed (fractions of the bottom and top of the column). The in vitro results showed that the EO and its fractions had a fungicidal action on B. cinerea and C. acutatum. In post-harvest tests with 'Isabella' grapes, rosemary EO and its fractions reduced the incidence and severity of gray rot and grape ripe rot in preventive and curative treatments. In the field trial conducted in an 'Isabella' grape vineyard, the concentrations of the bottom fraction of rosemary EO reduced the incidence and severity of the grape ripe rot. They did not change the qualitative parameters of the evaluated grapes, showing that the bottom fraction of rosemary EO can be applied in the vineyard as a biofungicide to control this disease.

Keywords

• Botrytis cinerea
• Colletotrichum acutatum
• natural products
• phytopathogens
• viticulture
• terpenes