Essential oil of cymbopogon flexuosus, vernonia polyanthes and potassium phosphite in control of bean anthracnose

Abstract

This study evaluated essential oils of Cymbopogon flexuosus (EOC), Vernonia polyanthes (EOV), and potassium phosphite (PP) in control of bean anthracnose caused by Colletotrichum lindemuthianum. This study assessed mycelial growth and conidial germination in vitro, scanning electron microscopy (SEM), and enzymes peroxidase (POX) and phenylalanine ammonia-lyase (PAL). EOC and EOV in doses 1,450 and 1,320 μL L-1 reduced disease severity by 57.2 and 37.6%, respectively. Major components identified in EOC were geraniol 46.8% and nerol 33.4%, and germacrene-D (42.2%) and bicyclogermacrene (17.2%) in EOV. SEM images showed that PP, EOC and EOV reduced mycelial growth and emission of germ tubes. PP and EOC increased POX and PAL rates in bean tissue. Bean anthracnose was controlled by direct antifungal activity of PP and EOC and induction of defense enzymes