The non-reducing sugars varied from 1.10% to 1.70%. The lowest and the highest non-reducing sugar contents were recorded in genotypes PSR-22 and PCR-9305 respectively in healthy leaves whereas in case of diseased leaves the non-reducing sugar contents varied from 0.79% (PCR-9305) to 1.95% (Varuna). The magnitude of reduction in this case was 22% due to occurrence of disease. Once the pathogen establishes its introduction in the host tissues, it starts feeding the nutrients from host and simple sugars are by far the first nutrient to be taken up by the fungi. Several workers have studies the alterations in the reducing and the non-reducing sugar contents due to pathogenic attack. The reducing sugar content varied from 3.52% to 4.50% in case of healthy tissues. This range was recorded from 3.0% to 3.70% in case of tissues infected by A. brassicae. Non-reducing sugars recorded a range of variation from 1.15% to 1.65% in healthy tissues and 0.88% to 1.10% in diseased tissues. The non-reducing sugars ranged from 1.10% to 1.70% and 0.79% and 1.95% in healthy and diseased tissues respectively. In the opinion of author the disease causes a derangement in the host plant metabolism and the simple sugars are the first preference for the nutrition of parasite. This might be cause of decline in the simple sugar. With the growth and proliferation of pathogen further breakdown of sugars might convert non-reducing sugars into reducing sugars, which might easily be utilized by pathogen.