Reaction of maize hybrids to Northern corn leaf blight and common rust, and chemical control of Northern corn leaf blight

André Schoffel,Carolina Cardoso Deuner,Juliane Nicolodi Camera,Jana Koefender,Carlos Alberto Forcelini,Diego Pascoal Golle

doi:10.1590/1808-1657000082018

Abstract

ABSTRACT: Northern corn leaf blight (NCLB) and common rust are among the primary fungal diseases affecting maize production. This study aimed to evaluate the susceptibility of ten maize hybrids to NCLB and to common rust and to verify the efficiency of fungicides in the chemical control of Exserohilum turcicum. In the first experiment, hybrids Pioneer (30F53, P1630H, P2530), Monsanto (AG 8045, AG 9045), Dow AgroSciences (2A550, 2A106 and 2B587) and Syngenta (SYN7205 VIPTERA, SW 3949 TL) were used and in the experiment for effectiveness of fungicides in the control of NCLB. The efficiency of fungicides propiconazole, azoxystrobin, cyproconazole + azoxystrobin, prothioconazole + trifloxystrobin, benzovindiflupir + azoxystrobin, cyproconazole + azoxystrobin + mancozeb were tested in the Pioneer P1630H hybrid. In both experiments, the leaf disease severity (%), yield and the weight of one thousand seeds were evaluated. The experimental design was carried out in randomized blocks with four replicates. The hybrids SYN7205, P2530, SW 3949 TL, 2B587, AG 9045, 2A550, P1630H, 2A106 and AG 8025 showed the smallest areas under the common rust severity progress curve. Hybrids AG9045, 30F53, and 2A550 presented the smallest areas under the NCLB progress curve. Hybrids AG8025, 2B587, P1630H, AG9045, 2A106, 2A550, present the highest yields. The fungicides prothioconazole + trifloxystrobin present the highest chemical control efficiency for NCLB and the lowest area under the disease progress curve (AUDPC).

Highlights

Maize crops are of great importance for the Brazilian economy, ranking as the second crop type with the largest grain production in the national territory, and with a large share of exports
Brazil is the third largest maize producer in the world (USDA, 2015), with most of its production concentrated in the second harvest (CONAB, 2016), known as safrinha
The severity of Northern corn leaf blight (NCLB) and common rust in the first year was evaluated, and only the severity of NCLB was evaluated in the second year

Summary

Introduction

Maize crops are of great importance for the Brazilian economy, ranking as the second crop type with the largest grain production in the national territory, and with a large share of exports. Brazil is the third largest maize producer in the world (USDA, 2015), with most of its production concentrated in the second harvest (CONAB, 2016), known as safrinha. Among the many causes that affect maize yield, we can mention fungal diseases as one of the main factors responsible for damages in productivity. There is a large number of fungi species that affect maize, but only a few cause significant losses. The distribution of these fungi in Brazil varies according to the region and to the growing period.

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Conclusion