Journal of Phytopathology (2021) 169, 139-148

Rafaela Araújo Guimarães, Edgar Zanotto, Paul Esteban Pherez Perrony, Lidia Almeida Salum Zanotto, Leonardo José da Silva, José da Cruz Machado, Felipe Augusto Moretti Ferreira Pinto, Henrique Novaes Medeiros, Renzo Garcia von Pinho, Itamar Soares de Melo, Júlio Carlos Pereira da Silva, Fernanda Carvalho Lopes de Medeiros and Flávio Henrique Vasconcelos de Medeiros (2021)
Integrating a chemical fungicide and Bacillus subtilis BIOUFLA2 ensures leaf protection and reduces ear rot (Fusarium verticillioides) and fumonisin content in maize
Journal of Phytopathology 169 (3), 139-148
Abstract: Fungicides in maize production under tropical conditions reduce losses from foliar diseases, but only a few reduce ear rot incidence or mycotoxin contamination in kernels. Biocontrol agents (BCAs) may reduce postharvest losses but their efficacy has not been demonstrated in field conditions. Here, we evaluated the use of bacterial isolates in tandem with fungicides on Fusarium verticillioides incidence and fumonisin content. After an early screening, Bacillus subtilis and Streptomyces araujoniae isolates were used in field trials. Maize plants were sprayed twice: at the end of the vegetative stage (V9) and at the beginning of the reproductive stage (R1). Sprays were made by applying water, B. subtilis strain BIOUFLA2, S. araujoniae strain ASBV-1T, or fungicide (cyproconazole + azoxystrobin) in different combinations, totalling nine treatments. Ten days later, all maize ears were inoculated with F. verticillioides. Plants were assessed for foliar diseases, grain yield, F. verticillioides incidence and fumonisin content in kernels. The treatment with two fungicide sprays reduced most of the foliar diseases but not F. verticillioides incidence in kernels. Twice-sprayed B. subtilis and S. araujoniae reduced F. verticillioides, but did not protect leaves against other pathogens. All treatments encompassing a fungicide followed by one of the BCAs reduced F. verticillioides incidence compared to control. Twice-sprayed fungicide increased fumonisin by 50% compared to water control, while fungicide followed by B. subtilis decreased the fumonisin content by 40%. Replacing the second chemical spray with S. araujoniae did not reduce the fumonisin content but provided a higher yield than a twice-sprayed fungicide. Exclusive use of chemical fungicides may not ensure higher grain quality and yield, but the integration with B. subtilis BIOUFLA2 can accomplish both.
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Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
control - general
Research topic(s) for beneficials or antagonists:
application technology

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Fusarium verticillioides	Maize/corn (Zea mays)
Bacillus subtilis (antagonist)	Fusarium verticillioides	Maize/corn (Zea mays)