Allelopathy Effect of Trichoderma spp. and Some Plant Extracts against Pythium aphanidermatum (In-vitro)

Abstract

Background: Serious seed-borne and soil-borne pathogens are existing at the rhizosphere area, many species of Pythium can cause seed rot and damping-off disease. The application of plant extracts and biological agents as alternative ways for the management of plant diseases has recently become an important variable component for Integrated Pest Management, so plant metabolites regarded as eco-friendly where plants play an important role in the control of diseases. The current study amid to evaluate the allelopathy effect of two species of biological agents particularly Trichoderma spp. and some plant extracts against the soil-borne pathogen P. aphanidermatum on cucumber seedlings under laboratory conditions. Methods: In this study laboratory investigation during 2018, used the allelopathy effect of two species of Trichoderma (T. harzianum and T. hamatum) and five plant extracts, in Three conc. 10.000, 20.000 and 30.000 ppm, to control damping-off disease in cucumber caused by Pythium aphanidermatum instead of using chemicals fungicides. Result: Our study observed that Trichoderma spp., have a high inhibitory effect on the tested pathogen, but in the assay of plant extracts, only some with different concentrations had a significant effect against P. aphanidermatum (in-vitro). Cinnamomum cassia, Syzygium aromaticum and Eucalyptus globulus were most affective from all other five tested plant extracts, where the concentration of 30.000 ppm gave the highest inhibitory effect against P. aphanidermatum, while Psidium guajava and Lawsonia inermis extracts showed a lower inhibitory effect on radial growth of P. aphanidermatum.