الفهرس 
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Abstract
Sugar beet (Beta vulgaris L.) is belongs to Chenopodiaceae family and recently considers the most important sugar crop for sugar production in Egypt. Sugar beet crop is conceded to be most promising and economically crop around the world. The cultivation area of sugar beet in Egypt has markedly increased from 16,900 feddens in 1982 to 594,248 feddens during 2018/2019 .Nawadays it ranked firest before sugar cane (Saccharum officinarum L.). Sugar beet plants attacked with many diseases throughout growth periods such as seedling damping off disease which caused during the first growth stage in plant life, leaf spot diseases are consider the most attacking sugar beet plants and effect on root weight, sugar percentage and consequently the amount of sugar yield production. The survey was carried out in the average 2015/2016 and 2016/2017 growing seasons in different locations in Northern and mid - Delta of Egypt i.e. Kafr El- Sheikh, El-Behaira, El-Gharbia, governorates. Seven districts from Kafr El- Sheikh governorate and three districts from both El-Gharbia and El- Behaira governorates as well as one location from of tested were chosed. The highest disease severity (77.6 and 75.2%) was noticed on sugar beet at El-Hamoul and Sidi-Salem districts, in Kafr El-Sheik governorates. While the lowest disease severity (41.7 %) was recorded on sugar beet at Damanhour district. Results showed that, all the tested plant extracts, natural oils,chemical inducers, biocontrol agents and fungicides have reduced significantly the linear growth of C. beticola. ethanol Piper nigrum extract, Ricinus communis oil, salicylic acid (SA), Trichoderma koningii T1 followed by B. subtilis (B1) and the fungicide Eminents were the most effective treatments in reduced the linear growth of C. beticola compared with control. Results showed that, all treatments increased some growth parameters TSS,leaf area , Chlorophyll content, Root weight, Sucrose and Purity (%). Also all treatments increased some antioxidants enzymes such as catalase (CAT), Peroxidase (POX), and Polyphenol oxidase(PPO), in leaves of Pleno sugar beet cultivar plants infested with C.beticola, under laboratory conditions.