SURVIVAL, DEVELOPMENT AND FECUNDITY IN EUSEIUS-FINLANDICUS, TYPHLODROMUS-PYRI AND KAMPIMODROMUS-ABERRANS (ACARI, PHYTOSEIIDAE) FEEDING ON THE SAN-JOSE SCALE QUADRASPIDIOTUS-PERNICIOSUS (COCCINA, DIASPIDIDAE)

Studies on juvenile survival, development and reproduction of Euseius finlandicus Oudemans, Typhlodromus pyri Scheuten and Kampimodromus abe rrans Oudemans feeding on crawlers of the diaspidid San Jose scale Qua draspidiotus perniciosus Comstock were conducted in the laboratory at 25 +/- 1 degrees C, 65 +/- RH and 16 h photoperiod. Immature life stag es as well as adult females readily accepted crawlers as prey. All pre datory species preying upon scale crawlers were able to complete devel opment and to sustain reproduction during a 10-day-period. Immatures o f E. finlandicus and K. aberrans had a low juvenile mortality, whereas nearly 50% of T. pyri protonymphs died. Mean development from larva t o adult took 5.6 days in E. finlandicus, 13.2 days in K. aberrans and 17.4 days in T. pyri. E. finlandicus had a higher fecundity (0.7 eggs/ day/female) than T. pq ui (0.5 eggs/female/day) and K. aberrans (0.4 e ggs/female/day). However, San Jose scale crawlers must be considered a suboptimal prey. Its nutritional value is discussed in relation to th at of more adequate food sources. Data on development and fecundity ar e also discussed in relation to other phytoseiid species feeding on ar moured scale insects.