Petunia.
Petunias are vulnerable to a large number of viruses. The single virus we detect most often in petunias, tobacco mosaic virus. However, some symptoms can alert you on the presence of other pathogens: brown spots, mosaic, deformation, chlorosis, mottle, stunting…
To diagnose your petunias culture, see the list of pathogens below and choose the type of test kit that suits you.