Bionomics of Choristoneura rosaceana12

Abstract

Choristoneura rosaceana (Harris) has been studied, primarily, in relation to its occurrence on apple. It is bivoltine under New York conditions. However, populations of the first, or summer generation, are only about 25% as large as the spring generation. This reversal of an expected population increase is apparently attributable to the scarcity of suitable food in July when first generation larvae are active. First-instar larvae appear to require actively growing leaf or fruit tissue for successful establishment. Survival in summer is enhanced through an unusually large egg production in the species and the active dispersal habits of the newly hatched larvae in which some become air-borne. Diapause was facultative in the geographic race occurring in New York. This race lends itself readily to continuous rearing when provided suitable living food (actively growing apple trees or fava beans), a temperature of 27°C, and a day of 16 hours light and 8 hours dark.