Good Morning,
Most houseplants, if grown under proper cultural conditions (proper light, humidity, air circulation, and water) experience very few disease problems. However, plants under stress are weakened and more susceptible to infection. 
Some of the common houseplant diseases and their symptoms, along with management tips, are described in the following table.
Preventing, Diagnosing, and Correcting Common Houseplant Problems (psu.edu)

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