الفهرس Only 14 pages are availabe for public view
 |  | from | 147 |  |  |
| | | from | 147 | | |
Abstract
This study was conducted to study the pathogen variability as well as disease distribution, epidemic patterns and control trials of Cercospora leaf spot disease ”CLS”. Results revealed that, CLS was condensed ”20-75%” in Delta Governorates, negligible ”4-8%” in Nubaryia region, and rarely observed in Beni-Suef, Menia and Fayoum Governorates. Significant differences were found among C. beticola isolates with respect to morphological, physiological and pathological characters. All tested isolates were capable to produce cercosporin in their culture media. Sb-1 isolate, was the highest cercosporin producer and SW-1 was the lowest one. Analysis of protein banding patterns of C. beticola showed that they separated to two subgroups. Separated groups were neither related to the host of isolates nor their geographic origin. All tested C. beticola isolates were virulent and differed significantly in their aggressiveness to Oscar poly cultivar under greenhouse conditions. The highly aggressive isolates ”Sb-1, Sb-6, Sb-18 & Sb-17” were the highly cercosporin producers, and the least aggressive ”Sb-7, Sb-13 & SW-1 were the lowest producers. The fungus was capable to infect, sugar beet, table beet, fodder beet and Swiss chard, while Sun flower, cotton, and maize plants, were free from infiction. Fungus was also capable to infect, sugar beet plants, 45 days after planting and up to 90 days. Sugar beet cultivars varied in their susceptibility to CLS infection. Oscar poly was the most susceptible cultivar ”33.33-35.00% D.S” while Kaw mera was the most resistant ”4.33%-8.33% D.S”.