Spread of Raspberry Leaf Curl Virus

No definite pattern of spread of leaf curl virus in red raspberry could be observed within an experimental plantation over a 7-year period. When a source of the virus was located at the ends of six 45-meter rows and allowed to spread over the period from 1962 to 1968, approximately 50% of the plants became infected. Transmission of the virus from infected to healthy plants did not follow along the rows but was scattered throughout the plantation. Despite a definite increase in the population of the vector, Aphis rubicola, over the 7-year period, the number of newly infected plants each year remained quite constant.