Número mínimo de aplicações de fungicidas no controle das cercosporioses da cultura do amendoim

• Autor(a) principal: Ruas, Anderson Robert [UNESP]
• Data de Publicação: 2014
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/121910
• topic: Amendoim; Fungicidas; Cercospora; Oilseeds

The early and late leaf spot in peanut crop are responsible for an important economic damage. Represents by Cercospora arachidicola and Cercosporidium personatum, the early and late leaf spot can occasion production damages in the peanut crop between 50 – 70 %. Among the control measure, the use of contact and systemic fungicide are important. Currently, the sprays are previous established on a set 14 – 15 days schedule, beginning in the 20-30 days after the plants emerge. The previously established of fungicides application has generate a huge problems, related to the bad positioning and the use of fungicides, like in the wrong moment of application, or in the absence in fundamental moment to the control of the disease. It was evaluated the efficiency and a minimum number of fungicides applications in the control of early and late leaf spot in peanut crop. The fungicides evaluated were chlorothalonil, epoxiconazol + pyraclostrobin in the dosages of 4 ml and 2.4 ml/L, applied over 15 days, in field condition located in Jaboticabal and Ibitinga, state of São Paulo . Fungicides were applied using a CO2 pressurized backpack sprayer, and flow of 250 L of spray per hectare. It was adopted the randomized block design, with 6 treatments and 4 repetition. Each sample unit corresponded to an area of 22.5 m2. The variable evaluated were severity of early and late leaf spot symptoms, numbers of leaf scars, fresh weight of stem and grain weight, held on a date of 20/03/2014, in Jaboticabal, and 23/04/2014, in Ibitinga, the evaluation of grain mass held in date of 30/03/2014, in Jaboticabal, and 30/05/2014, in Ibitinga. Through of the data were used exploratory multivariate analyzes by hierarchical clustering method, processed with the Euclidean distance as a measure of similarity between samples, and Ward as the method of connection groups. It was concluded that there is need for at least five applications ...