effect of powdery mildew disease on quantity and quality of sugar beet yield in kermanshah province

to study  the effect of powdery mildew on sugar beet yield and percentage of sugar losses sugar percent losses, ten genotypes were compared in a factorial  experiment based on  randomized complete block design with 3 replications and two factors. the first factor was spraying treatment with two levels and the second were genotypes. inoculation was carried out using the pathogens' conidial suspension. disease severity index was calculated based on the wangs' scale 6 weeks after inoculation. data showed that  fungicidal application increased root yield( 16.5 %). however the positive response of the genotypes to chemical control of powdery mildew was variable. increase in root yield varied from 0.5 tons/ha in bulk 7233 to 19.7 tons/ha in the genotype 7233 p.107 response of genotypes was also different in sugar percent and in the sprayed treatment sugar percent increased. maximum sugar increase (2.2 %) was obtained in the genotype 7233 p.107.