[excerpt] Accidentally introduced into New Jersey about 1925, the European pine sawfly, Neodiprion sertifer (Geoffroy), now inhabits most of the Northeastern and North Central States and Ontario, Canada. Red pine, Pinus resinosa Aiton, and most other native and exotic pines within its range are susceptible to attack. Few attack records are available for ponderosa pine, P. ponderosa Douglas ex Lawson, because this pine is uncommon in eastern North America. Soraci (1939) ob- served egg clusters and larval feeding on planted red and ponderosa pine in New Jersey; Benjamin et al. (1955) found egg clusters on ponderosa pine in Illinois and recorded more intensive attacks on red pines nearby. However, quantitative data on the relative susceptibility of ponderosa pine to sawfly attack have never been reported.
Wilson, Louis F.
"Relative Susceptibilities of Three Ponderosa Pine Sources to European Pine Sawfly (Hymenoptera: Diprionidae) Attack in Michigan,"
The Great Lakes Entomologist: Vol. 1
, Article 6.
Available at: http://scholar.valpo.edu/tgle/vol1/iss1/6