Foliar fungicide efficacy against maize white spot: Insights from a nine-year meta-analysis

Maize white spot (MWS) caused by Pantoea ananatis in Brazil is among the most impactful foliar diseases affecting maize production, often resulting in significant yield losses. To assess how different fungicide types influence disease control and yield response, we analyzed data from 87 independent field trials conducted over a nine-year period (2016–2024) across five Brazilian states and Distrito Federal. Eight fungicide treatments were included, each evaluated in at least 19 trials with available disease severity data. Two treatments involved solo active ingredients (MANCozeb and ChLORothalonil), while six were premix formulations (DIFenoconazole + PYDIflumetofen, PYRAclostrobin + EPOXiconazole, PYRAclostrobin + FLUXapyroxad, AZOxystrobin + TEBUconazole + MANCozeb, PYRAclostrobin + FLUXapyroxad + MEFEntrifluconazole, and TRiFloXystrobin + PROThioconazole + BIXafen). Percent control, estimated by back-transformation from a log-scale network meta-analysis, ranged from 53.2% to 71.3%. All treatments, except PYRA + EPOX and MANC, achieved mean efficacy values above 60%. Yield gains from three sequential fungicide applications ranged from 694 to 1,081 kg ha⁻¹, with the highest increases observed for DIF + PYDI, PYRA + FLUX + MEFE, and TRFX + PROT + BIX. These findings, derived from nearly a decade of field research, reinforce the importance of fungicide applications in reducing maize white spot severity and improving yield. Moreover, they support current resistance management strategies that advocate for the combination of site-specific and multisite fungicides to optimize disease control and sustain long-term effectiveness.