African Journal of
Agricultural Research

  • Abbreviation: Afr. J. Agric. Res.
  • Language: English
  • ISSN: 1991-637X
  • DOI: 10.5897/AJAR
  • Start Year: 2006
  • Published Articles: 6914

Full Length Research Paper

Managing brown leaf spot disease in rice: Insights into Bipolaris oryzae pathogenesis and management strategies

Amponsah Jephthah
  • Amponsah Jephthah
  • Kwame Nkrumah University of Science and Technology, Accra Rd, Kumasi, Ghana.
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Richard Tuyee Awuah
  • Richard Tuyee Awuah
  • Kwame Nkrumah University of Science and Technology, Accra Rd, Kumasi, Ghana.
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Atta Kwesi Aidoo
  • Atta Kwesi Aidoo
  • CSIR-CROPS Research Institute, Kumasi, Ghana.
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Zippora Appiah-Kubi
  • Zippora Appiah-Kubi
  • Kwame Nkrumah University of Science and Technology, Accra Rd, Kumasi, Ghana.
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Jerry Fenteng Asamoah
  • Jerry Fenteng Asamoah
  • CSIR-CROPS Research Institute, Kumasi, Ghana.
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  •  Received: 14 October 2024
  •  Accepted: 06 December 2024
  •  Published: 31 January 2025

Abstract

Bipolaris oryzae is a severe Ascomycete pathogen responsible for brown leaf spot in rice, resulting in significant yield losses in both quantity and quality. This disease is prevalent worldwide, affecting most rice-growing regions and holding historical significance for many rice-producing countries. The pathogen can infect rice at any growth stage, manifesting symptoms on various plant parts. Initial symptoms appear as small, circular, dark brown to purple-brown spots, which can progress to circular or oval lesions with light brown to gray centers and reddish-brown margins, eventually leading to abscission. Although chemical fungicides have provided some control, they often have detrimental effects on the environment and human health. Fungicides such as Carbendazim, Propiconazole, Dithane M-45, and Ridomil have demonstrated varying degrees of efficacy in controlling the disease, with synthetic fungicides showing the highest effectiveness, achieving up to 100% inhibition. Biological agents that prevent pathogen colonization, reduce pathogenicity, and strengthen plant immune responses have been analyzed as the most environmentally friendly alternative for disease control. Despite the global significance of B. oryzae, there is limited comprehensive data on the synergistic application of biocontrol agents, microbiome engineering, prevalence, genetic diversity, and correlation with yield loss. Further research is necessary to address these knowledge gaps and enhance disease management strategies.

Key words: Biocontrol, chemical control, disease symptoms, pathogen variability, management, rice production.