Developmental Zero, Effective Accumulative Temperature, and Nurnber of Annual Generations of the Garden Pea Leafminer, Chromatomyia horticol (Goureau) (Diptera: Agromyzidae) in the Oshima District of Hokkaido

Abstract

Developmental periods of Chromatomyia horticola on garden pea were determined by laboratory experiments under three temperatures from 15 to 25°C. Although the developmental period showed a tendency to shorten as temperature elevated, the number of adult emergence at 25°C was decreased. The developmental zero and effective accumulative temperature in the stage from egg to adult emergence were calculated as 6.0°C and 270.2 day-degrees, respectively. On the basis of these data and daily averaged temperature, C. horticola was estimated to undergo seven generations in a year in southern Hokkaido. In unheated vinylhouse, seven peaks was also observed on the seasonal occurrence of feeding punctures, eggs and mines on 50 top leaves of garden pea.