Another harmful disease to your cannabis plants is called pythium. There are three common strains of this disease, but for the purpose of this article, all of them will simply be referred to as pythium. Symptoms and treatments for all of them are the same.One of the first indicators of a Pythium infection is the yellowing of your marijuana leaves for no apparent reason. They will soon wither and die, and you might not even notice until it is too late. Also, the tips of the roots may be ...