Sclerotium rolfsii is a pathogenic fungi caused rot roots of carrot In this study the best growth of Sclerotium rolfsii showed that the mycelial gave maximum sclerotial production growth was very  fast at 22 °C , also the pathogen  grow and produce sclerotia at temperatures range at minimum and maximum between 10 Cº and 22° C . Among of the nutrient slots on  the pathogen , there are Potassium (K), Copper (Cu) and Citric acid are proved to be essential elements which required  for controlling and inhibiting the pathogen growth,. Using these salts gave promising results to inhibit S.rolfsii growth like potassium at all in contrast citric acid didn't prove the same effect, but copper was good at the high concentrations.