AUTHOR=Persaud Rajendra , Saravanakumar Duraisamy , Persaud Mahendra , Seepersad Govind 

TITLE=Biologicals and New Generation Fungicides in the Management of Blast Disease in Rice

JOURNAL=Frontiers in Sustainable Food Systems

VOLUME=5

YEAR=2021

URL=https://www.frontiersin.org/journals/sustainable-food-systems/articles/10.3389/fsufs.2021.797441

DOI=10.3389/fsufs.2021.797441

ISSN=2571-581X

ABSTRACT=<p><bold>Background:</bold> Blast is a devastating disease in rice production. The current research tested the efficacy of biologicals and fungicides against blast. Aqueous extracts of <italic>Azadirachta indica, Ocimum basalicum, Cymbopogan flexousus, Thymus vulgaris, Aloe vera, Tagetes patula</italic>, Cordia curassavica, <italic>Aegle marmelos, Allium fistulosum</italic>, Syzygium aromaticum, and <italic>Calotropis gigantea</italic> were tested <italic>in vitro</italic> at 5, 10, and 15% concentrations against <italic>Magnaporthe oryzae</italic>. Also, two isolates, <italic>Bacillus cereus</italic> OG2L and <italic>B. subtilis</italic> OG2A, and one isolate, <italic>Azotobacter</italic> SAG19, and, similarly, five new generation fungicides were evaluated at three different doses against blast pathogen <italic>M. oryzae in vitro</italic>. The treatments that exhibited the best performance <italic>in vitro</italic> were further evaluated against blast disease under field conditions.</p><p><bold>Results:</bold> Extracts of <italic>T. patula</italic> (5%)<italic>, C. gigantea</italic> (5%), <italic>C. curassavica</italic> (10%), <italic>A. fistulosum</italic> (10%), and <italic>A. marmelos</italic> (15%) showed greater than 81% inhibition to <italic>M. oryzae in vitro</italic>. Likewise, all three biocontrol agents, <italic>viz. B. cereus</italic> OG2L, <italic>B. subtilis</italic> OG2A, and <italic>Azotobacter</italic> SAG19, demonstrated more than 50% inhibition of mycelial growth of pathogen <italic>in vitro</italic>, and the commercial formulations of fungicides Propineb, Trifloxystrobin+Tebuconazole, Tebuconazol+Triadimenol, <italic>Bacillus subtilis</italic> Strain QST 713, and <italic>Cinnamon Oil 8%</italic>+<italic>Clove Oil 2%</italic> also significantly inhibited <italic>M. oryzae</italic>. Under field conditions, C. curassavica (10%), <italic>A. marmelos</italic> (15%), <italic>C. gigantea</italic> (5%); <italic>B.cereus</italic> OG2L; <italic>B.subtilis OG2A</italic>; Proineb and Trifloxystrobin+Tebuconazole were effective in reducing disease in addition to yield enhancement.</p><p><bold>Conclusion:</bold> Overall, the plant extracts (<italic>C. curassavica at 10%, A. marmelos at 15%, C. gigantea at 5%</italic>); bio-agents (<italic>B. cereus</italic> OG2L, <italic>B. subtilis</italic> OG2A both at 2g/l), and new generation fungicides Antracol 70WP (Proineb) at 2.5 g/l and Nativo 75 WG (Trifloxystrobin+Tebuconazole) at 0.5 g/l provided effective control against blast disease and superior plant growth and yield compared with other treatments and untreated control.</p>