The Effect of Water Extract of Ocimum basilicum and the Fungal Biocontrol Agent Trichoderma harzianum on Fungi causing Damping-off of Okra

The present study includes the effect of water extract of basil (Ocimum basilicum) leaves and culture filtrate of the biocontrol agent Trichoderma harzianum on the mycelial growth of damping-off fungi of Okra, Rhizoctonia solani, Macrophomina phaseolina and Fusarium solani. All tested concentrations (0, 5, 10, 15, 20, 25, 30 mg/ml) of the aqueous extract of O. basilicum caused significant reduction on the linear growth of the pathogenic fungi and reaching 100%, at some concentrations. The inhibition increased with the increase in concentration of the extract from 5 to 30% for both R. solani and M. phaseolina. The inhibition reached 97.04% for F. solani.
All concentrations of the extract gave the same effect on the dry weight of pathogenic fungi and caused maximum inhibition (100%) to R. solani and M. phaseolina. Addition of three concentrations 10, 20 and 30% of culture filtrate of the biocontrol fungus caused significant decrease in the growth of fungi and the effect increased with the increase in concentration to 30%. Maximum inhibition was noticed with M. phaseolina and F. solani (98.16 and 96.48% respectively). Similar reduction inhibition on the dry weight of fungi, was recorded when various concentrations of the culture filtrate of the biocontrol fungus was added to the liquid media.
Combining the aqueous extract and culture filterate of T. harzianum showed more inhibitory efficiency on the growth of all pathogenic fungi and their dry weights as compared with individual treatments alone and reached 100% at concentration 30%.