Fungicidas sistêmicos associados à multissítio: efeito sobre a severidade da ferrugem asiática e a produtividade da soja

Abstract

Asian soybean rust (FAS), whose etiological agent is the fungus Phakopsora pachyrhizi, is the main disease of the crop. Due to its high biological plasticity and ease of dissemination, it is difficult to control this disease. The objective of this work was to evaluate the efficiency of the combination of fungicides from specific (systemic) and multisite (mancozeb) sites on the progress and control of soybean Asian rust, as well as its effect on crop productivity in the 2016 harvest / 17 and 2017/18. The treatments evaluated were: T1) trifloxystrobin + prothioconazole; T2) azoxystrobin + benzovindiflupyr; T3) trifloxystrobin + prothioconazole + mancozeb; T4) azoxystrobin + benzovindiflupyr + mancozeb; T5) mancozeb; and T6) control. The efficiency of fungicides on pathogen control was assessed by disease severity and area estimation below the disease progress curve (AUDPC). The components of yield and productivity were also determined. The combination of systemic fungicides and mancozeb reduces the severity and progress of Asian rust in soybean, cv. BMX Lança, reaching a control above 81%. Treatment T3 was highlighted in the two crops with greater control over FAS and higher productivity among other treatments. For the thousand grain weight, in the 2017/18 harvest, lower values were observed than the average of cv. (177 g). The combination of systemic fungicides and mancozeb reduces the severity of FAS and is an important tool for the management of Phakopsora pachyrhizi resistance, with the potential to preserve the useful life of specific fungicides.