SELECTION OF BIOCONTROL AGENTS FOR CONTROL OF ONION WHITE ROT DISEASE | ||||
| Journal of Plant Production | ||||
| Article 11, Volume 31, Issue 5, May 2006, Page 2863-2879 PDF (5.92 MB) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jpp.2006.236000 | ||||
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| Authors | ||||
| S. T. Shehata,1; M. M. Mosbah2; Late M. F. Hegazi1 | ||||
| 1Department of Plant Pathology, Faculty of Agriculture, Ain Shams University, Shobra EI-Kheima, Cairo, Egypt. | ||||
| 2Plant Pathology Research Institute, Agricultural Research Center, Giza, Egypt. | ||||
| Abstract | ||||
| Isolation of bioagents was carried out from rhizoplane of healthy onion plants, 70 and 120 days after transplanting from different governorates, i.e. El-Behera; EI- Sharkia; Beni-Swif and El-Menia. Only 21 isolates from the obtained 331 isolates have prevented sclerotial formation of Sc/emtiurn cepivorum on NYDA medium. The inhibition zones of mycelial growth of S. cepivorum after 14 days were 13, 9, 7, 4 and 2 ml for isolates Pseudomonas flourescens; Bacillus llcheniformis 10014; Bacillus licheniformls 6011; 7012 and Chaetomium globosum respectively. Most of treatments of potting medium, with bacterial isolates soon after onion seeds sewing, increased the percentage of onion seed germination. The highest increase 195 °/o was achieved by isolates B. licheniformis 6011 and B. amylo/iquefac/ens 109. The promising biocontrol agents that had promotion toward onion seed germination and plant growth were tested in greenhouse for their potential control of onion white rot. At 50 or 100 scierotia/ Kg potting medium, the best reduction in dead plants was achieved by treatment with P. flourescens, B. licheniformis 6011. T. harzianum, B. amyloliquefaciens 109, C. globosum or Paenibacll/us polymyxa 9014. Clear significant increase in plant height was occurred by treatment with P. flourescens followed by B. licheniformis 6011, C. globosum, B. amo/iquefaciens 109, Trichoderma harzianum and Paenibaci/lus polymyxa 9014. However, in field experiment all applications were highly effective in reducing the percentage of dead onion plants due to white rot infection till the end of growing season (4.5 months from transplanting), The isolates, P. flourescens, B. llchenlformis 6011, B. amo/iquefaciens 109 or T. harzianum isolates were the most effective on disease control in the field. Significant increase in bulb yield was recorded with all tested isolates especially those of bacteria. Keywords: Biological control, Onion, White rot, Sclerotium cepivorum, Pseudomonas flourescens, Bacillus licheniformis, B. amyloliquefaciens, Trichoderma harzianum, Chaetomium globosum | ||||
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