The development of Lophodermium pinastri in conifer nurseries and plantations in North America

The recent outbreak of Lophodermium needlecast in North America first appeared in 1966 in forest nurseries on red pine (Pinus resinosa) and Scotch pine (P. sylvestris). Dispersal of infected nursery stock throughout North America has created a serious needlecast problem in Scotch pine Christmas tree plantations. Two biotypes of L. pinastri are present. The pathogenic strain may be a recent introduction. The fungicides maneb and chlorothalonil are being used for control.