DefinePK

Abstract

Background and Objective In Egypt, peanut is one of the most important crops for exportation and local consumption. It is a good source of dietary proteins and contains high lipid that is rich in unsaturated fatty acids. Damping-off and root rot diseases are the main constraints in peanut production. The current study aimed to determine the effect of cell-free filtrates of Trichoderma harzianum T, Saccharomyces cerevisiae Y andor Rhizobium japonicum R on the control of damping-off and root rot diseases in peanut. Materials and Methods Fusarium solani, Rhizoctonia solani and Sclerotium rolfsii were the common causal pathogens isolated from naturally infected peanut, causing damping-off and root rot diseases. Peanut seeds cv. Giza 6 were soaked for 4 h in each tested treatment before sowing treatments also used as a foliar spraying at 28 days from sowing. While, fungicide Rizolex-T50 was used as seed coating at 3 g kg1501 seeds. Results In the in vitro tests, the combined application of TYR culture filtrates at the rate of 121 and the dual application of TY completely inhibited the mycelial growth of the pathogenic fungi. While, R alone had no significant effect on the fungal linear growth. In vivo, the best protection against damping-off and root rot diseases were observed under fungicide Rizolex-T50 application followed by the combination of TYR 121. All culture filtrates of T, Y, R and their combinations stimulated the activity of polyphenol oxidase, peroxidase and chitinase. The highest activity was obtained by the combined application of TYR 211 for polyphenol oxidase and peroxidase. While the highest chitinase activity was observed with Y treatment alone. The application of TYR increased the percentage of plant survivals and improved plant growth and yield. Conclusion The application of a mixture of biotic culture filtrates was more effective in decreasing the infection of soil borne fungi in peanut. Wherein, a commercial production of a mixture of growth filtrates of TYR is recommended for therapy both damping-off and root rot diseases in peanut plant.