Factors Influencing Adult Emergence from Diapausing Sorghum Midge, Contarinia sorghicola (Diptera: Cecidomyiidae)1

Abstract

Sorghum midge, Contarinia sorghicola (Coquillett) diapause was terminated in the laboratory, and factors affecting adult emergence from diapausing larvae were investigated. Temperatures in the range from 20 to 30°C were optimum for diapause termination and adult emergence. Diapausing larvae exposed to moist conditions at 30°C began to emerge as adults after 12 days of incubation. Based on adult emergence rates per day, an emergence threshold temperature was estimated to be 14.8°C. Exposure to 12 to 13 days of continuous moisture at 30°C was essential for diapause termination and adult emergence. Moisture acted to initiate diapause termination, but diapausing larvae were unable to accumulate shorter periods of moisture toward the 12- to 13-day requirement. Photoperiod had no significant effect on the termination of larval diapause.