Some properties of four viruses isolated from carnation plants

Four viruses isolated from commercial carnation varieties were transmitted to Sweet William plants (Dianthus barbatus L.), which react characteristically with them. Two, carnation ring-spot virus and carnation mottle virus, have spherical particles, the first about 19 m mu. and the second about 32 m mu. in diameter. Both survive heating for 10 min. at 85 degrees but not at 90 degrees C., and remain active at room temperature in sap from Sweet William for more than 2 weeks. They are not serologically related, and have not been transmitted by Myzus persicae. The other two viruses are transmitted mechanically and by M. persicae. Carnation vein mottle virus inactivates in 10 min. between 50 and 55 degrees C. and at room temperature between 10 and 14 days; attempts to produce an antiserum against it failed. Rod-like particles not seen in sap from healthy Sweet William were occasionally seen in sap from infected plants. Carnation latent virus has rodshaped particles. It produces no symptoms in carnation and Sweet William plants; its presence is readily detected by serological tests. When transmitted by aphids to sugar beet, it sometimes causes the older leaves to become yellow. Carnation latent virus inactivates in 10 min. between 60 and 65 degrees C. heating and at room temperature between 2 and 3 days. A virus serologically related to carnation latent virus occurs in apparently healthy potato plants of many different varieties.