[Cynthia, Prescott, AZ]

Sorry to tell, but mostly it is just experience. A digital camera and the forum is a great combination to get you thru the learning stage. One correction. Fungal problems do not fit the soft/wet description. That would make the problem bacterial. Fungal problems usually are just a change in color to black, with the sometimes presence of a sinking of the tissue surface. Another problem from a special kind of fungus is a wilting of the tissue, which is cause by fusarium fungus. Some fusariums have a red lining just under the skin on the rhizome, at the base of the plant. But some fusarium fungi do not produce this characteristic red lining. Fusarium does not respond to many systemic fungicides, so I tend to recommend Thiophanate Methyl (Clearry's 3336, Bonomyl, Fertilome Halt, ...), which does work on fusarium, and other fungi too.