Controlling of rot root pathogens on cucumber using some plant extracts and bio-control agent Trichoderma harzianum

Abstract

Different fungal pathogens that cause rot root disease have a significant impact on cucumbers, which has a tremendous economic limitation on the yield of this important vegetable crop. The current study aims to examine the effect of cold aqueous extract of three plants (Acacia farnesiana, Myrtus communis and Nerium oleander) on the radial growth and the biomass of some pathogenic fungi (Rhizoctonia solani and Macrophomina phaseolina) with the presence of Trichoderma harzianum as a bio-control agent. Fungal pathogens were isolated from root parts of infected cucumber plants that were collected from different regions of Najaf province, while the bio-control fungus was obtained from the Bio-control Laboratory, Faculty of Agriculture - University of Kufa. Results of the current study showed that 20% of the cold aqueous extract of M. communis powder was superior to the rest of the studied extracts in inhibiting the radial growth of studied fungi, as the radial growth of R. solani reached 3.49cm, M. phaseolina 3.02cm, and T. harzianum 3.67cm. Thely apparent effect of the same extra extract on the growth of the fresh and dry biomass of the aforementioned fungi. The outcomes demonstrated that the 20% concentration of cold aqueous extract of M. communis  also increased the percentage of seed germination and the fresh weight of cucumber plants. The cold aqueous extract of M. communis leaves and T. harzianum as a biological can be used , to inhibit the growth of both pathogens of rot root disease, thus protecting cucumber seedlings and producing healthy plants.