Natural Mortality of Erioischia brassicae (Bouche) (Diptera, Anthomyiidae) During the Immature Stages of the First Generation

Abstract

1. A brief account is given of the biology of Erioischia brassicae. 2. Methods are described for the enumeration of the populations of the different stages of the life-cycle. 3. Five years' records of the population losses occurring during the first generation are summarized, and possible causes of mortality are listed. 4. Discussion of the mortalities occurring during each stage of the life-cycle suggests that the egg mortalities are the most important.