Efficacy of the fungus Trichoderma harzianum Rifai and some nutritive elements in protecting seeds and plants of some tomato hybrids from infection with the fungi F. oxysporium f.sp. lycopersicum (Sacc.) Snyder & Hansen and Rhizoctonia solani Kühn

Abstract

This study was conducted to evaluate the efficiency of the antagonistic fungus Trichoderma harzianum and the nutritive elements comprised iron and manganese and the interaction between them in resistance of seed decay and seedlings dampping-off disease of some tomato hybrids (Mujstm, Faten, Super Marimond and Hybrid) caused by the fungi Rhizoctonia solani and Fusarium oxysporium f.sp. lycopersicum. Results showed that the addition of the two elements into the nutrient medium PDA (Potato Dextrose Agar) had varying effects on the growth of T. harzianum and R. solani and F. oxysporium f.sp. lycopersicum, where it was found that the addition of manganese at a concentration of 0.40 g commercial material/L was the most effective concenteration in encoragment of the growth of T. harzianum and inhibition of the growth of the pathogenic fungi R. solani and F. oxysporium f.sp. lycopersicum, where the rate of the radial mycelial growth of the fungi reached 8.08 and 2.33 cm, respectively, which significantly differed from the control treatment. It was also observed that the fungus T. harzianum had high antigonistic potential to significantly inhibit the pathogens R. solani and F. oxysporium f.sp. lycopersicum on PDA medium containing manganese or iron elements added at a concentration of 0.40 g commercial/ L. Among the other tested varieties, representing Mujsm, Super Mmarimond and Hybrid, tomato variety "Faten" was found to be highly susceptible to the pathogenic fungi; wherease the Hybrid variety was more resistant to R. solani and F. oxysporium f.sp. lycopersicum among the other varietes.The interaction between the biological control fungus and nutrient elements had high efficiency in protecting seeds and tomato plants from infection with R. solani and F. oxysporium f.sp. lycopersicum. Tomato plants treated with T. harzianum, manganese showed a significant effect on the pathogenic fungi reflecting positively on increase of the rate of seeds germination, plant height and dry weights of root and shoot systems in comparsion with the other treatments applied in the experiment.