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In vitro and in vivo evaluation of microbial agents for management of rice blast disease in Tanzania

Ibrahim Hashim: Sokoine University of Agriculture

<div>The main objective of this study was to evaluate the effect of two microorganisms, <em>Trichoderma asperellum</em> and <em>Bacillus subtilis,</em> on the management of rice blast disease caused by <em>Pyricularia oryzae</em>. The dual culturing technique and pot experiment was conducted to test the antagonistic effect of <em>T. asperellum</em> and <em>B. subtilis</em> against <em>P. oryzae</em>. Both <em>T. asperellum</em> and <em>B. subtilis</em> showed a high antagonistic activity with a percentage inhibition radial growth (PIRG) > 75 % compared to Linkimil 72 WP with PIRG 21 - 23 % and the negative control PIRG 0 %. In a pot experiment, disease incidence (DI) and percent disease severity (PDS) 14 days after inoculation (DAI) and 21 DAI indicated that DI increased by 11.34 % on plants treated with <em>B. subtilis</em>, followed by <em>T. asperellum </em>(7.26%), and Linkimil 72 WP (0.15%) compared to the control (no spray) (19.94%). Similar trends were observed on disease severity, which increased by 8.2% for <span><em>B. subtilis</em></span> followed by <span><em>T. asperellum</em></span> (0.30%) and Linkimil 72 WP (0.78%) compared to the negative control (9.17%). The increase in lesion size was significantly low (0.15 mm) in the plants treated with <em>T. asperellum</em>, followed by <span><em>B. subtilis</em></span> (0.21 mm), and Linkimil 72 WP (0.47 mm) compared to the negative control (0.91 mm).</p> <p></div>