Abstract
The ligustrum fruit midge, Asphondylia sphaera MONZEN and the aucuba fruit midge, Asphondylia sp. have been noted to overwinter in their fruit galls in the first larval instar and to develop into further stages in the following spring. In order to determine the developmental zero point and to predict the emergence season of adult midges based on the total effective temperature, ligustrum and aucuba fruit galls containing first-stage larvae were collected from Shiroyama, Kagoshima City in January and February 1982, and were incubated at 6 different temperatures under a photophase of 11L13D. The galls were dissected at intervals of 5 days to observe the developmental stages of the species. The first instar-stage of the ligustrum fruit midge and of the aucuba fruit midge normally developed into further stages at temperatures above 13°C, and 14°C, respectively. However, the larval development of both species seemed to be retarded by a temperature of 22°C which is distinctly higher than the average tempera-ture in February or March in Kagoshima City. The date when 50% of the adults emerged from the ligustrum fruit, galls could be accurately predicted based on the ther-mal totals above the developmental zero point.
