This document summarizes a study that investigated the effect of vitamins on endopolygalacturonase (Endo PG) production in Alternaria cepulae, a fungus that causes leaf blight disease in onions. When grown in pectin medium supplemented with vitamins, all vitamins except calcium pantothenate increased mycelial growth and Endo PG activity. The highest Endo PG production and mycelial growth occurred when all vitamins were added together. This suggests that vitamins play an important role in enzymatic activities and metabolism in A. cepulae.