Uso da biomassa cítrica no controle de doenças da soja

Abstract

Actually soybean is the main product of Brazilian agricultural sector. This crop requires a high technology input to yield increases. Diseases are one of the problems that could impair the yields. The control of diseases, in the most cases, increases costs of production and moreover has a negative impact in the environment. For this reason, the induction of resistance is appointed as a alternative control method. This method is established by the activation in the host plant, of latent defense mechanisms. Thus, aims this work were verify the effect of citric biomass at concentrations of 0.75; 1.5 and 3.0 mL L-1 , for the control of mildew (Peronospora manshurica), powdery mildew (Microsphaera diffusa), rust (Phakopsora pachyrhizi) and late season diseases (Cercospora kikuchii and Septoria glycines), as well as to verify the effects on production components and productivity of soybean. Plants without treatment and treated with Piraclostrobin + Epoxiconazol (0.5 L ha-1 ) were used as control. Results show that citric biomass at 3 mL L-1 reduced the mildew severity in 62% and powdery mildew severity in 35%, however did not reduce severity for rust and late season diseases. Yields did not differ between the plants treated with different citric biomass concentrations as compared with control plants without treatment and were 20% lower as compared to fungicide treated plants. This could be a result of increases of metabolic costs, resulted by the induction of resistance mechanisms. Results suggesting that, the citric biomass could contribute to control of soybean diseases, as well supply sequential studies.