Chemical characterization and anti-fungal activity of plant extracts and essential oils on the Bipolaris oryzae and Gerlachia oryzae phytopathogens

Abstract

The chemical composition of plant essential oils, and the in vitro effect of plant extracts and plant essential oils on the phytopathogens Bipolaris oryzae and Gerlachia oryzae was investigated. Liquid extracts of ten plants were obtained by maceration and then dialyzed using a 3kDa retention membrane. The plant essential oils from seven plants were analyzed by gas chromatography. To determine anti-fungal activity two methodologies were used: Kirby-Bauer and incubation. In this research we identified the major compounds of the essential oils: 93.77 % β-thujone in the Tanacetum vulgare oil; 40.61 % β-thujone in Artemisia absinthium; 45.89 % nananone and 41.07 % undecanone in Ruta graveolens and; 38.78 % citronellol and 19.55 % carvone in Malva sp. This research showed that the Cymbopogon citratus, P. alliacea, S. officinale and Malva sp. extracts have more potential to control G. oryzae best while the S. officinale and Lantana camara extracts are most efficient against B. oryzae. Among the plant essential oils, Zingiber officinale, C. citratus and Malva sp. had the greatest potential to control both phytopathogens. This is the first report of the activity of plant extracts and essential oils against the phytopathogens G. oryzae and B. oryzae, two important pathogens of irrigated rice.