Abstract :
Techniques optimal for the mass culture of a lady-beetle, Eriopis connexa Mulsant, imported into the United States for biological control of the Russian wheat aphid Diuraphis noxia (Mordvilko) were determined using three prey species and two temperature treatments. Also, survival of eggs and pupae after various periods of storage at 4°C was monitored. Conditions that favored production of large beetles (11.8 mg) were not the conditions providing the highest larval survival (91.7%), which in turn were not the conditions promoting the most rapid larval growth (6.3 days). An index based on larval developmental time, larval survival, and adult weight indicated that the most optimal rearing condition for beetle production was to use the Russian wheat aphid as prey at 34°C. The least favorable conditions involved feeding beetles the pea aphid Acyrthosiphon pisum (Harris) at 34°C. Eggs cannot be kept for more than 1 day at 4°C without incurring 30+% mortality; after 14 days mortality was 83%. Pupae were stored at 4°C for 3 weeks with no mortality but pupae stored longer than 7 weeks suffered 100% mortality.
