Do all plant viruses cause diseases in plants?

Not all plant viruses cause diseases in plants. Some plant viruses do not cause any noticeable symptoms in infected plants, and these are known as symptomless viruses. These viruses may or may not have negative effects on the plant's health or productivity, and their presence may only be detected through laboratory testing.

Additionally, some plant viruses may cause mild or transient symptoms that do not significantly impact the health or quality of the plant.