Schaub, L.P., Mani, E., Bloesch, B., & Schwaller, F. 1995 Distribution of Quadraspitiotus perniciosus (San Jose scale) in Switzerland based on interpolated pheromone trap data.. Bulletin OEPP 25: 631-636.

Notes: Geographic information system used to create a surface representation of 1990 pheromone-trap catch data of Q. perniciosus; the major tree-fruit production regions of Switzerland are at risk but still free from this scale.