Dados do Trabalho

Título

EFFECT OF APPLICATION OF POTASSIUM PHOSPHITE ON THE CABERNET SAUVIGNON GRAPE BUNCH AND EVALUATION OF ANTIFUNGAL ACTIVITY AGAINST THE FUNGUS Botrytis Cinerea in vitro

Introdução

There is currently a demand to reduce the application of fungicides in agriculture, including viticulture. Studies have been conducted to identify for alternative compounds with antifungal action, aiming to maintain and improve grape quality. In this study, the effect of potassium phosphite on the in vitro development of the fungus Botrytis cinerea was evaluated, as well its viability as an alternative to conventional fungicides on grapevines.

Material e Métodos

In vitro, potassium phosphite was added at concentrations of 1.00, 2.00 and 4.00 mL/L and control (without application) to the previously sterilized Potato Dextrose Agar culture medium. Then, a 5 mm diameter disc of mycelium from the pure culture of Botrytis cinerea was placed in the center of the petri dish and mycelial growth was evaluated. In the field, the experiment was carried out by applying a potassium phosphite solution (2.00 mL/L) directly to the grape bunch during the phenological cycle of the vine and a sample was kept as a control (without application). The difference between treatments was the number of applications (1, 2 or 3 applications) of the potassium phosphite solution carried out during the maturation period. Vineyard productivity parameters, physicochemical properties, total polyphenols, antioxidant activity (ABTS method), total monomeric anthocyanins and organic acid profile of the grapes were evaluated.

Resultados e Discussão

In vitro analysis demonstrated that potassium phosphite (4.00 mL/L) inhibited more than 50% the mycelial growth of the fungus B. cinerea. The application of potassium phosphite directly to the grape bunch during ripening did not negatively influence vineyard productivity compared to the control, and the treated grapes showed satisfactory maturation, regardless of the treatment. The application of phosphite influenced the concentration of organic acids, with tartaric acid being the majority, ranged from 6.03 to 6.75 g/L, values higher than the control sample (5.67g/L). Furthermore, the number of applications positively influenced the content of polyphenols, anthocyanins and antioxidant activity of grapes, highlighting the treatment that received 3 applications.

Conclusão

The use of potassium phosphite demonstrated potential antifungal action in vitro, and a viable sustainable alternative against fungal diseases of grapevines.