Doses de fungicida multissítio associadas a sítio específicos no controle de ferrugem da folha e rendimento de trigo

Abstract

Wheat is a widely used cereal in human and animal nutrition. However, the incidence of diseases leads to losses in its productivity and quality. The objective of this study was to evaluate the efficiency of applying doses of the multisite fungicide mancozeb, combined with a program using systemic (or site-specific) fungicides, to control leaf rust and improve wheat yield. The experiment was conducted at the experimental area of the Universiade Federal da Fronteira Sul - Campus Erechim, using a randomized complete block design with 4 replications. The cultivar used was TBIO Ello CL, and 6 treatments were evaluated as follows: T1 - control without fungicide application; T2 - site-specific program (fluxapyroxad + pyraclostrobin + epoxiconazole; trifloxystrobin + tebuconazole; and thiophanate-methyl); T3 - program + 1.5 kg mancozeb ha-1; T4 - program + 2.0 kg mancozeb ha-1; T5 - program + 2.5 kg mancozeb ha-1; and T6 - program + 3.0 kg mancozeb ha-1. The area under the disease progress curve (AUDPC) and disease control (%) for leaf rust were estimated. Additionally, the following parameters were quantified: spike length (cm), number of filled and shriveled grains, hectoliter weight (HW), thousand grain weight (TGW, g), and yield (kg ha-1). Treatment 4 was found to be the most effective, providing 98.17% control for wheat leaf rust and ensuring higher productivity (4195.54 kg ha-1), spike length (7.93 cm), and the greatest number of filled grains (47) per spike. These results indicate that the dose of 2.0 kg mancozeb ha-1, combined with site-specific fungicides, not only provides satisfactory control of leaf rust but also increases the yield and productivity of TBIO Ello CL wheat.