The mutual influence between the effects of virus infections on plant development and the plant developmental program on the outcome of a virus infection is reviewed, focusing on individual developmental traits. The effects of certain infections on typical developmental traits range from dramatic to almost negligible, depending on the specific combination host/virus. The chapter focuses on the impacts of viral suppressors of RNA silencing and viral movement proteins transgenically expressed in the plant, and of true virus infections on certain developmental traits. The stages of plant development and their influence on the outcome of virus infections are also reviewed. The study of these mutual interactions may shed light on both sides of it. In the past, certain aspects of virus life cycle have been highly instrumental in the study of plant physiology and biochemistry. A thorough characterization of the interactions from the standpoint of plant development may be similarly useful. Conversely, the virus life cycle can only be fully understood in the context of its interaction with the host, and the different developmental stages of a plant can provide further insight into the role of the different viral components.