Not all indoor and patio/alfresco plants are susceptible to pests and diseases.
Calatheas for example tend to get Alternaria leaf spot and fusarium root rot. To ensure this doesn’t happen it is vital to get your watering right and not to over water your plants or leave large amounts of moisture sitting on the leaf. Overhead watering can cause diseases such as leaf spot, however, many of the indoor varieties can get the common insects such as scale, aphids and mealy bugs mainly because of the conditions they are grown in are more favourable for these insects to thrive in.