Posicionamento de fungicidas para o controle de ferrugem da folha do trigo

Abstract

Wheat is the second most produced cereal in the world and plays a crucial role in food security, both for the human population and for its use in animal feed. However, it faces a number of diseases; among them, leaf rust (Puccinia triticina) stands out as one of the main and most harmful to the crop. The objective was to evaluate the efficiency of fungicide application programs to wheat leaf rust control, as well as the impacts in relation to productivity and crop yield. Experiments were conducted in the UFFS Experimental Area - Campus Erechim (RS) during the 2022 and 2023 crop seasons, in a randomized block design, with 5 treatments and 4 replications. The cultivar used was TBIO Ello CL, with a moderately resistant response to leaf rust. The treatments consisted of: T1 - control, without application of fungicides; T2 and T3 - fungicide applications positioned at the elongation, rubberization and flowering stages; and T4 and T5 - fungicide applications positioned only in the rubbering and flowering stages. The area under the disease progress curve (AUDPC) and control (%) of leaf rust; hectoliter weight (PH, kg hL-1), thousand grain weight (TGW, g) and productivity (kg ha-1), were estimated For AUDPC and leaf rust control, there was a statistical difference between the treatments that received fungicide application in relation to the control, with disease control reflected in greater productivity when compared to these treatments and the control, which ensured an increase in 23 sc ha-1, in the 2022 crop season, and 10.8 sc ha-1 in the 2023 crop season. In both seasons, the average PH was 66.2 kg hL-1, which classified the wheat as not suitable for milling and flour production. The average PMG was 21.5 g and was below that indicated for the cultivar (32 g). Because TBIO Ello CL cultivar is moderately resistant to leaf rust, the use of two or three fungicide applications did not impact the productivity result, and, in both harvests, the treatments only differed from the control. However, in the 2023 crop season, as environmental conditions favored the incidence of Fusarium head blight, a reduction in productivity can be seen when the treatments were compared with those in the 2022 crop season.