Remarques sur L'écologie deQuadraspidiotus perniciosus Comst. dans le Midi méditerraneen (Hom. Diaspidinae)

Summary

Ecological studies onQuadraspidiotus perniciosus Comst. (Homoptera-Diaspidinae) have been realized in the mediterranean zone of France. New investigations concern:

• - life cycle of San José Scale. There are three generations per year, the scale hibernates as a diapausing first instar larva;

• - natural mortality: climatic factors have prevailing importance on the growth of populations, during the spring by their action on young larval instars;

• - natural enemies; Predators:Cybocephalus sp.,Chilocorus bipustulatus l. have no economic interest; Collected parasites are:Aphytis proclia wlk.,Aspidiotiphagus citrinus craw.,Prospaltella aurantii how. Their numerical importance varies during the year. But their life cycle is determined by two factors: climate and host, the second depending also of the first.Aphytis proclia has three generations and a possible partial fourth. Its cycle is only conditioned by seasonal factors.

Both endophagous parasites have a life cycle with three generations and a possible partial fourth. In winter diapause of host induces dormancy of the parasite. But during spring summer and autumn, climatic factors alone regulate the evolution of Hymenopterous parasites.