Biological control of Sclerotinia minor in lettuce using Trichoderma species

A Trichoderma harzianum isolate (C52) and a Trichoderma viride isolate (TV1), with known activity against Sclerotinia spp. in laboratory screens, were tested for their ability to control disease caused by Sclerotinia minor in lettuce crops in glasshouse trials (1996)(1997).Different application methods of T. harzianum C52 were also tested, namely soil incorporation, pellet formation and a transplant root spore dip.In the first trial, T. harzianum soil incorporation significantly reduced disease incidence by 50% compared to the untreated control, and was comparable to a standard carbendazim fungicide treatment which gave 57% reduction in disease incidence.In the second trial, carbendazim and all three methods of T. harzianum application significantly reduced disease incidence by 55-78%, compared to the control and there were no significant differences between the treatments.The results suggest that T. harzianum (C52) has potential value as a biological control agent to control lettuce drop caused by S. minor in glasshouse systems.