Rearing Delphastus catalinae (Coleoptera : Coccinellidae): Practical experience and a modeling analysis

Delphastus catalinae (Horn) (Coleoptera: Coccinellidae) was mass reared to support field studies addressing augmentation and colonization for control of Bemisia argentifolii Bellows and Perring (Homoptera: Aleyrodidae) in sou thern California. Beetles were reared on B. argentifolii infested poinsetti a plants grown inside greenhouses located in northern California. Potted pl ants, reared from rooted cuttings, were cycled through the rearing system o ver ca, a 12-week period, then discarded. A total of 174 245 adult beetles were harvested over a 20-week period. Each plant averaged 46 adult beetles (range 21-89) over the same period of time. Harvesting strategies were inve stigated using a computer simulation model based upon published and hypothe sized reproduction and survivorship parameters. Results suggest that remova l of approximately 50% of adults per week produced a stable and maximum pro duction of beetles. Actual harvest rates were between 40 and 60% of availab le beetles. The cost of producing each adult was estimated at US$0.22, with the major cost being labor at 86% of the total.