Extrato de alho e óleo vegetal na quebra de dormência de gemas e no controle de doenças da videira

Abstract

This study aimed to evaluate different doses of garlic extract (GE) and of vegetable oil to soy in break dormancy of buds of the grapevine Cabernet Sauvignon and control of grape diseases. For all experiments prepared the GE by maceration of cloves in centrifugal juice. In the experiment installed in Dezem Winery, Toledo state of Paraná, grapevine Cabernet Sauvignon were sprayed with the following treatments: T1) control (no treatment), T2) 20 mL L -1 GE, T3) 40 mL L-1 GE, T4) 60 mL L-1 GE, T5) 20 mL L- 1 SO (soybean oil) T6) 20 mL L1 EA + 20 mL L-1 SO, T7) 40 mL L-1 GE + 20 mL L-1 SO, T8) 60 mL L-1 GE + 20 mL L-1 SO; T9) 20.8 g L-1 H2CN2 (hydrogen cyanamide). And after 30 and 45 days after treatment (DAT) evaluated the percentage of bud break. The best results were provided by treatment H2CN2 with 78.1% of buds at 45 DAT. Treatment 20 mL L-1 and another 20 mL L-1 SO, also stimulated the dormancy, reaching 48.4% bud break, differing from treatment H2CN2 which reached only 22.1%. Other experiments were performed in the laboratory of Plant Pathology, Department of Agronomy, Universidade Estadual do Centro Oeste and field conditions in Guarapuava-PR. These experiments we used doses of 0, 5, 10, 15, 20, 25 or 30 mL L-1 GE. We evaluated the mycelial growth of Elsinoe ampelina and Phomopsis viticola in vitro, adding the GE before and after sterilization autoclave, at 3, 5, 7 and 9 days after inoculation. For both fungi, there was drastic reduction in the growth of E. ampelina and e Phomopsis viticola, especially at a dose of 30 mL L-1 GE between 8.92 to 100% when adding before and after sterilization, respectively. And inhibition completely to Phomopsis viticola from 5 mL L1 to GE without autoclave. Another variable analyzed was the germination of E. ampelina and Plasmopara viticola divided three study with addition treatments to 2.5 mL L-1 SO, except in the Plasmopara. The germination of the E. ampelina reviewed in periods 2 and 4 hours of incubation at 24°C and constant light in seconds and 6 and 12 hours in the dark 20°C. Bouth the GE and SO inhibited the germination of the pathogens above 85%. In the sprayed if these treatments every 15 days or 30 mm of precipitation and evaluated the severity of anthracnose of grapevine cv. Isabel, turned in AUDPC (area under the curve progress of the disease). A reduction in AUDPC of 63.37% at 2.5 mL L-1, compared treatments control. The effect of GE was examined on the germination of Plasmopara viticola and AUDPC of anthracnose of grapevine Isabel, in vivo. Besides the treatment with doses of EA, said treatment with Bordeaux mixture (1:1:100) and mancozeb (2 g L-1) only in the germination test, because it is an organic vineyard. The syrup and mancozeb had lower percentage germination of Plasmopara viticola in 62.6 and 55.4%, respectively. In the field, we observed 52% reduction in AUDPC brown rot in relation to the absolute control (no treatment), from 20 mL L-1 of extract of garlic. The OV had no effect on germination and severity of the pathogen.