Authors : M. Akrami , As. Ibrahimov , E. Valizadeh and Abolfazl Asadi Dizaji
Abstract: In this investigation, the ability of nine Trichoderma harzianum isolates which had been isolated from soil and root rapeseed field were compared to one isolate of Bacillus subtilis and 2 per thousand benomyl solution to control rapeseed sclorotinia rot. These isolates had shown good control of Sclerotinia sclerotiorum in in vitro condition. In this experiment seed of Talaye variety were planted in pots of 15 cm diameter and offer seedling emergence they were thined to one seedling. The plants were maintained at 20�2�C and 90% R.H until flowerbuds appeared. After flowerbud appearance the plants were inoculated with 7mm diameter mycelium disk put on low, middle and uppear leaf of each plant. The controls were treated with 107 mL 1 of spores of the antagonist fungus, a 108 mL 1 bacterial suspension and with a 2 per thousand benomyl solution separated at 2 different times. One set of control plants were treated 3 days ahead of inoculation and another set were treated on the same day. Assessment of the inhibitory effect of treatment on fungal pathogen were done 3 days after inoculation of the leaves by measuring the diameter of the lesions produced and comparing with sterile water control. The results obtained show that: there is a significant difference between the biological treatment agents. The shortest diameter of the lesions on inoculated plants belonged to T1 and T3 isolates of T. harzianum and also to B. subtilis. There was no significant difference between T4 and B. subtilis in other word, use of any of these three would have same effect. The two isolates T1 and T9 of T. harzianum and B. subtilis when used at the same time that plants are inoculated with the pathogen would have the most effect. Comparing the bonomyl effect with that of biological agents, it had significantly superior effect. The position of the leaf on the plant had not significant effect.
M. Akrami , As. Ibrahimov , E. Valizadeh and Abolfazl Asadi Dizaji , 2008. The Ability of Trichoderma harzianum Isolates in Controlling Rapeseed Sclerotinia Rot in Comparison with the Effects of Bacillus subtilis and Benomyl Fungicide. Research Journal of Biological Sciences, 3: 856-859.