0023-6152

AA00697606

12855

Unrefereed

0023-6152

AA00697606

The effect of seven constant temperatures on the development of the Myanmar strain of Cotesia vestalis,　(Haliday), a larval parasitoid of diamondback moth Plutella xylostella (L.) was studied in the laboratory.　Developmental times for immature stages were inversely proportional to temperature between 15 and　33°C but increased at 35 °C. Total developmental times from egg to adult emergence decreased from 63.7　to 9.4 d for temperatures from 15 to 33 °C, with pupae requiring less time for development than the combined　egg and larva stage. Both linear and nonlinear (Logan equation VI) models provided a reliable fit of　development rates versus temperature for all immature stages. The lower developmental thresholds that　were estimated from linear regression equations for the egg to pupa, pupa to adult, and total combined　immature stages were 8.9, 10.1, and 9.4 °C, respectively. The degree-day accumulation was calculated as　200 DD for development from egg to adult emergence. By fitting the nonlinear models to the data, the　upper and optimal temperatures for egg to pupa, pupa to adult and total development stages were calculated　as 38.2 and 35.0, 35.0 and 31.8, 30.5 and 31.3 °C, respectively. These data are useful for predicting population　dynamics of C. vestalis under field conditions.