Uso de fungicidas para controle da mancha branca em milho

Abstract

White spot is considered one of the main leaf diseases of corn crop, as it has significantly increased its occurrence in producing regions, causing yield losses and great challenges to manage it. Thus, the application of pesticides is an effective control alternative to these diseases. The objective of this work was to evaluate the effect of fungicide combination for white spot control and corn crop yield under second crop conditions. The experiment was conducted in Uberlândia - MG and the hybrid used was Status. The treatments consisted of different fungicides, as follows: (T1) control (no fungicide application); (T2) azoxystrobin (125 g L-1 i.a.) + flutriafol (125 g L-1 i.a.) at stages V8, VT and R2; (T3) azoxystrobin (125 g L-1 i.a.) + flutriafol (125 g L-1 i.a.) at stages V8, VT and R2 + mancozeb (750 g kg-1 i.a.) at stages VT and R2; (T4) azoxystrobin (125 g L-1 i.a.) + flutriafol (125 g L-1 i.a.) at stages V8, VT and R2 + chlorothalonyl (500 g L-1) at stages VT and R2; and (T5) azoxystrobin (125 g L-1 i.a.) + flutriafol (125 g L-1 i.a.) at stages V8, VT and R2 + fluazinam (500 g L-1) at stages VT and R2. The traits evaluated were: plant height and ear insertion height, percentage of green leaf area, wet stem density, dry stem density, final stand, disease progress curve (AACPD) for severity and grain yield data. In this experiment no differences were observed between plant heights, ear insertion heights and final stand, however, when compared to the control, the fungicide treatments showed better disease control, yield, wet stem density, dry stem density and leaf area percentage. Therefore, it was concluded that all fungicide treatments resulted in lower white spot severity, higher stem integrity and higher grain yields when compared to the control, highlighting significantly T5 (phenylpyridinylamine + strobilurin and triazole) for presenting the smallest white spot AACPD, better stem integrity and the highest grain yield.