Effect of Trichoderma species on damping off diseases incidence, some plant enzymes activity and nutritional status of bean plants

S: Fusarium solani and Rhizoctonia solani are the common causal pathogens causes the damping off disease of beans (Phaseolus vulgaris L.) in Egypt. The antagonistic effect of four Trichoderma species, i.e. Trichoderma album, Triechoderma hamatum, Trichoderma harzianum and Trichoderma viride, was tested against F. solani and R. solani in vitro, in greenhouse and in field. In vitro tests, all Trichoderma spp. significantly reduced the mycelial growth of two pathogenic fungi. In greenhouse experiment, T. album, T. hamatum, T. harizianum and T. viride, as soil treatments, significantly reduced the preand post-emergence damping off disease incidence under artificial infection with F. solani and R. solani. Soil treatments with four Trichoderma species significantly reduced the incidence of damping off disease where the percentages disease incidence were in the range of 7.0 -20.0% and 2.4 – 6.5%, compared to 25.7 and 13.5% in control plants, at preand post-emergence stages ,respectively. The best protection to damping off disease was obtained by T. hamatum, followed by T. viride, T. album and T. harzianum, respectively. The treatments gave the highest plant survival (%) and improved the growth and yield parameters. Results showed that the levels of chitinase, peroxidase and polyphenol oxidase activities highly increased in treated bean plant compared in untreated plants. The macroand micro-elements content in treated bean plants was affected by Trichoderma species treatments compared to elements content in untreated plants. The relationship between plant nutrient content and some plant enzymes activity was studied. [Journal of American Science. 2010;6(9):486-497]. (ISSN: 1545-1003).