Effective Biocontrol of Rice Blast through Dipping Transplants and Foliar Applications

Abstract

Rice (Oryza sativa) is an increasingly popular food in Africa. As much as 30% of yields are lost due to blast disease caused by Magnaporthe oryzae. Several commercial biopesticides of Bacillus subtilis, Trichoderma asperellum, and Serratia sp. strains were evaluated under field conditions for their effects against rice blast and yield at one site in Kenya and three sites in Tanzania in 2020 and 2021. Each biopesticide was applied as a dipping treatment at transplanting, post-transplanting foliar spraying, or both. Using biopesticides not only achieved blast control but also increased grain yield, particularly in low-production regions in Tanzania, with a yield increase of >100%. For higher-production sites with low disease pressure, the yield increase through biopesticides over the untreated control was limited, although significant disease suppression was achieved. Dipping alone was sufficient to suppress disease and improve yield unless disease pressure was high. The differences among the three biopesticides varied with site/year but generally were small. Improved yield using biopesticides is unlikely to result solely from reduced blast development, but also from improved plant development. The present study suggests that these commercial biopesticides should be applied in rice production, particularly in subsistence farming.

Characterization of Endophytic Microorganisms of Rice (Oryza sativa L.) Potentials for Blast Disease Biocontrol and Plant Growth Promoting Agents

“…Among bacterial endophytes, the highest inhibition was found by B. licheniformis, followed by Stenotrophomonas rhizophila. Some of the known biocontrol agents namely Trichoderma species, Bacillus subtilis and Pseudomonas fluorescens have shown good results in managing rice blast [9][10][11]. The identified endophytes used in the study were found as good as other reported biocontrol agents for managing rice blasts.…”

“…Chemical fungicides are often used, resulting in the development of resistance to pathogens, environmental contamination, and effects on non-target microorganisms [8]. Biocontrol using endophytic microorganisms is an alternative management strategy and is being used throughout the world for the management of rice blast [9][10][11]. An endophyte is a fungal or bacterial microbe that spends all or part of its life cycle inhabiting the host plant's healthy tissues, usually without persuading disease symptoms [12].…”

Refinement of rice blast disease resistance QTLs and gene networks through meta-QTL analysis

“…Cultural, chemical, and biological strategies have been developed and deployed to control this disease. Biological control, such as the use of biocontrol agents 5 , 6 and deployment of resistant cultivars, is an eco-friendly approach. However, wide application, effectiveness, and durability can be achieved only through the identification of stable resistant sources and their utilization in crop breeding.…”

Formulation of Matrine Oil-Based Suspension Concentrate for Improving the Wetting of Droplets and Spraying Performance

“…Matrine, a tetracyclo-quinolizidine compound, exists in various leguminous plants such as Sophora flavescens Ait., S. alopecuroides L., and S. tonkinensis Gapnep. Matrine is widely used in medicine to treat various diseases and can be used to control pests and diseases in agriculture because it has a wide spectrum of activities, including insecticidal, antibacterial, antifungal, and antiviral activities [9][10][11][12][13]. More significantly, matrine degrades easily in soil and water [14,15] and is nontoxic to nontarget organisms [16].…”