Evaluation ofTrichoderma as a biocontrol agent forRosellinia necatrix

Different isolates ofTrichoderma harzianum andTrichoderma hamatum were isolated from naturally infected roots ofRosellinia necatrix. T. harzianum andT. hamatum isolates overgrew cultures ofR. necatrix placed simultaneously in petri dishes. Relative levels ofR. necatrix population were assessed by the avocado leaf colonization method.T. harzianum isolate T-8, significantly reducedR. necatrix colonization of avocado leaves in comparison to other isolates in artificially and naturally infested soils.R. necatrix inoculum decreased steadily over 4 and 6 week periods in artificially inoculated soil and naturally infested soil respectively when isolate T-8 was applied, to a point where noR. necatrix could be recovered. Disease incidence of almond seedlings was significantly reduced when isolate T-8 was added to naturally infested En-Zurim soil.