This disease of peaches has been transmitted by the geminate leafhopper, Colladonus geminatus, in exptl. work in Washington, Oregon, and Utah. A total of 39 transmissions have been secured. The latent periods thus far demonstrated for the virus in the insect have generally ranged more than 30 days, with one instance of 22 days. Some leafhoppers have remained infective for at least 58 days. Transmissions have been secured with single insects. The leafhopper was capable of carrying the disease to 3 trees in succession when moved at weekly intervals.