Efficacy of Carboxamide, Triazole and Strobilurin Fungicides on Corn Disease Management

Several pathogens cause maize crop losses, including Cercospora zeae-maydis (gray spot), Pantoea ananatis (white spot), Exserohilum turcicum (northern corn leaf blight), Puccinia sorghi (common rust), Puccinia polysora (southern rust), and Kabatiella zeae (eyespot/brown-spot). The use of sensors that provide NDVI (Normalized Difference Vegetation Index) can contribute to evaluation of the maize health of maize and also provide a means to estimate the potential corn production. Aiming to evaluate the effect of fungicides in the control of foliar corn diseases, and the correlation of NDVI with agronomic and pathological parameters in maize, two experiments were conducted (2013/14) in a randomized block design with split-plots (4 × 6) with four replications. The factor hybrid was, DKB390, P30F53, Fórmula and 2B587, and factor fungicide was: Untreated control (CO), Fluxapyroxad + Pyraclostrobin (50.1 + 99.9 g L-1), Benzovindiflupyr + Azoxystrobin (49.5 + 99), Bixafen + Trifloxystrobin + Prothioconazole (50 + 60 + 70), Trifloxystrobin + Prothioconazole (75 + 87.5) and the Total Control (TC = 8 applications of Fluxapyroxad + Pyraclostrobin). Three applications of fungicides were made. The variables assessed were area under disease progress curve (AUDPC), grain yield, and NDVI. Fluxapiroxade + carboxamide and Bixafen + Trifloxystrobin + Prothioconazole were effective in controlling: grey spot, white spot, southern rust and eyespot. Benzovindiflupyr + Azoxystrobin was effective in controlling common and southern rust. All fungicides favored increments in productivity and reduced the incidence of rotten grains and F. verticillioides grain rot. NDVI was positively correlated to yield and 1000-grain-mass and, negatively correlated to AUDPC of the diseases.