Controle alternativo da antracnose em cebolinha (Allium fistulosum L.) utilizando produtos derivados de vegetais

Abstract

The common chives (Allium fistulosum L.) is one of the main vegetables used in Brazilian cuisine. The leaf anthracnose caused by Colletotrichum sp. is the major disease of the chives culture in the Amazon. However, there are no fungicides registered with the Ministry of Agriculture, Livestock and Supply for this pathosystem. This study aimed to report the effect of plant-derived products such as precious shell of aqueous crude extracts (Aniba canelilla (HBK) Mez.), long pepper (Piper aduncum L.), hydrolats rosewood (A. rosaeodora Ducke), macacaporanga (A. parviflora Ducke), long pepper, long pepper essential oil and infusion in controlling anthracnose chives, caused by Colletotrichum sp. First, 4 isolated Colletotrichum spp. were obtained and it was confirmed its pathogenicity, however just one isolated was used. For the preparation of EBAs, 200 g of leaves were immersed in 800 mL of distilled water and it was kept for 24 h at room temperature. Since SOs and the HIDs were obtained by steam distillation by Clevenger apparatus (1 L water for 100 g of leaves), while infusion was used 200 g of fresh leaves immersed in 800 ml of distilled water heated to 70 °C, maintained for three hours in a dark container and closed at room temperature. OEs and HIDs were obtained by steam distillation by Clevenger apparatus (1 L water for 100 g of leaves), while infusion was used 200 g of fresh leaves immersed in 800 mL of distilled water heated to 70 °C, maintained for three hours in a dark, closed container at room temperature. The experimental design was completely randomized (DIC), with eight treatments: T1 (precious shell EBA), T2 (long pepper IN), T3 (rosewood HID), T4 (macacaporanga HID), T5 (pepper OE long), T6 (HID long pepper), T7 (EBA long pepper) and T8 (control-water); nine replicates per treatment, each plant was considered an experimental unit. The vegetable derivatives were diluted in distilled water and applied weekly for 50 days, in all aerial parts of the plant, at a concentration of 30 %. The evaluation consisted of computing all treatment with the absence or presence of disease symptoms. Data from the incidence of the disease in the plant (Yp = plant) and severity in the central leaves (Yf = central leaves) were used to calculate the respective areas under the disease progress curve, AACPDp and AACPDf. The mean data were compared using ANOVA and Tukey's test at 5% probability. The treatments significantly affected the health and productivity of spring onion plants. Provided average 40% reduction in incidence of the disease in the whole plant. Highlighted, there are treatments with HIDs of macacaporanga that inhibited 54.6% and long pepper with 52.4% inhibition and average reduction of 55.6% severity. Highlighted, long pepper infusion that inhibited 63.5%, the macacaporanga’s HIDs that inhibited 63% and long pepper that inhibited 62.9% compared with the control (water). Regarding productivity, the treatment caused 64.5% Average increases in of the final width of chives leaves compared to the witness. From these results, it is estimated that in the future, macacaporanga’s HIDs and long pepper will be used by chives producers in the states of Amazonas.