EVALUATION THE EFFl'CIENCY OF SOME BIOCONTROL AGENTS AND BELTANOL AGAINST RHIZOCTONIA SOLANI AND FUSARIUM OXYSI)ORUM THE CAUSAL OF SEEDROT AND DAMPING OFF DISEASE OF WATERMELON.

A. Farhan, Theyab; S. Juber, Kamil; H. Rasheed, Ahmed

	EVALUATION THE EFFl'CIENCY OF SOME BIOCONTROL AGENTS AND BELTANOL AGAINST RHIZOCTONIA SOLANI AND FUSARIUM OXYSI)ORUM THE CAUSAL OF SEEDROT AND DAMPING OFF DISEASE OF WATERMELON.
The Iraqi Journal of Agricultural Science
Article 1, Volume 39, Issue 2, 2008, Pages 68-78
Authors
Theyab A. Farhan; Kamil S. Juber; Ahmed H. Rasheed
Abstract
The study include control of seed rot and damping off disease of watermelon by using some of biocontrol agents. The result of antagonistic ability test of Trichoderma spp. on PSA culture media showed that all Trichoderma species (T. viride J T. hamatum and T. pseudokoningiii revealed a high degree of antagonistic against the pathogenic fungus F. oxysporum which were reached 1.9,2.0,1.7 respectively. The two antagonistic fungi T. pseudokoningii and T. vir ide also showed a high degree of antagonistic against the fungus R. solani which were reached 2.0 and1.8 respectively. while J T. hamatum failed to show efficacious antagonistic degree against the pathogenic fungus, the antagonistic degree in its treatment was 2.2. The Paecilomyces lilacinus fungus had a low antagonistic degree against R. solani and F. oxysporum which were 3.2 and 3.0 respectively. The bacteria Bacillus subtilis showed a highly antagonistic ability, where its using caused 66.6% and 44.4% growth inhibition against the two pathogenic fungi respectively . The Beltanol fungicide showed a higher efficiency in the growth inhibition of R. solani and F. oxysporum where the growth of two fungi completely inhibited . The two Biocontrol agents , T. pseudokoningii and B. subtilis and Beltanol fungicide showed efficiency in the protection of watermelon seeds and seedling from the infection by the two pathogenic fungi R. so/ani and F. oxysporum . The use of the two biocontrol agents cause increase the percentage of seed germination in the presence of the two pathogenic fungi R. solani and F. •oxysporum , the percentage of seed germination in their treatment reached 53.3% and 66.6% and 60%, 70% respectively , and reduced the percentage of disease severity with the presence of the two pathogenic fungi to 55.4% , 32.3% and 53.2% , 30.6% respectively, while the percentage of seed germination and disease severity in the Beltanol treatment in the presence of the two pathogenic fungi were reached 76.6% ,80% and 33.8% , 18.5% respectively compared with control treatment with the presence of the two pathogenic fungi R. solani and F. oxysporum only where the seed germination and disease severity were reached 6.6% , 10% and 93%, 90% respectively. All the biocontrol agents and the BeItanol fungicide treatments showed .increase in shoots and root in dry weights of compared with the treatment of the two pathogenic fungi only

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