A variety of natural and artificial substrates were tested for their suitability as oviposition sites for the predatory anthocorid bug Orius insidiosus. The bugs oviposited into models of beans constructed from Parafilm, but none of the eggs laid into these models hatched. In choice tests, beans stems were preferred to both bean pods and potato sprouts. Hatching rates at 100% r.h. were highest (59%) for bean pods and significantly lower for both potato sprouts (39%) and bean stems (29%). At 60% r.h., hatching rates for bean pods (39%), bean stems (34%) and potato sprouts (33%) were similar. At 30% r.h. hatching rates for all three substrates were less than 15%. The results suggest that bean stems can be used successfully as an alternative to bean pods for the mass rearing of these biological control agents.

Diets combining the eggs of Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) with corn pollen, green snap bean pods, and adult western flower thrips [Frankliniella occidentalis Pergrande (Thysanoptera: Thripidae)] were evaluated for their effects on the predatory anthocorid bug Orius insidiosus (Say). Nymphs fed only corn pollen did not complete development. Fourteen percent of the nymphs fed only green bean pod sections reached the adult stage. Females reared on a diet of bean pod sections did not oviposit. Nymphal survival, adult longevity, and fecundity were greatest for diets containing both E. kuehniella and green bean pods. When diets of bean pod sections and eggs of E. kuehniella were supplemented with pollen, egg production was slightly increased. Adult females provided with thrips were not more fecund than females maintained on a diet of eggs of E. kuehniella. Egg production increased significantly with the number of thrips consumed, demonstrating the importance of adult nutrition.

The western flower thrips [Frankliniella occidentalis (Pergrande)] (Thysanoptera: Thripidae) is a major pest of greenhouse crops (Broadbent et al. 1987; van der Veire and Degheele 1992; Chambers et al. 1993). Chemical control of F. occidentalis is difficult because of its cryptic behaviour and widespread resistance to insecticides (Immaraju et al. 1992). The insidious flower bug, Orius insidiosus (Say), is widely promoted as an effective biological control agent for this pest (Chambers et al. 1993; van der Veire and Degheele 1992; Castane and Zalom 1994) and its use has increased steadily since their introduction in the late 1980s. When our project was initiated in 1989, O. insidiosus was a little known and largely unavailable biological control agent. Now there are several domestic and international commercial sources of Orius spp. and these predatory bugs have become a focus of research in Canada, the United States, and Europe. At first it was difficult and costly to maintain cultures of only 100 or 200 individuals but now we can rear 50000 — 100000 Orius per week for less than $0.03 (Canadian) each.