Mathys, G., & Guignard, E. 1967 Quelques aspects de la lutte biologique contre le pou de San José (Quadraspidiotus perniciosus Comst.) à l'aide de l'aphélinide Prospaltella perniciosi Tow.. Entomophaga 12: 223-284.

Notes: Title in English: [Some aspects of biological control which serve to assist the aphelinid Prospaltella perniciosi Tow. against the San Jose scale (Quadraspidiotus perniciosus Comst.)] The aptitude to support extreme conditions is given for the thermic range but not in a satisfactory manner for the hygrometric range. Areas with extremely dry conditions where the humidity is lower than 50% during a long time are inconvenient for the parasite. This fact could explain why regions close to the California deserts, insufficiently watered, may bear plants with poorly parasitized San Jose scale populations. The scale is apparently more resistant to dry conditions. The possibility of survival of the parasite at low host densities is experimentally proved and is a very important quality. It is evident that the parthenogenetic strains are stimulated when bred at high differences in temperature during the light and dark phases. Another important quality of P. perniciosi is its aptitude to fly over relatively important distances of host-free land. In two cases the parasite flew 200 and 250 m on its search for hosts.