Estimation of Lower Temperature Threshold and Thermal Requirements for Development of Sesamia cretica (Lep., Noctuidae) Using "Degree-days" and "Ikemoto and Takai" Linear Models

In order to provide a phenological forecasting model, estimation of lower temperature threshold and thermal requirements are necessary. Therefore, current study was carried out to estimate lower temperature threshold and thermal requirements of Sesamia cretica Led., using Degree-days and Ikemoto and Takai linear models. Developmental times of the corn stem borer immature stages were determined at five constant temperatures, 18, 20.5, 24, 27, and 30 (±0.5)ºC, a photoperiod of 16L: 8D h and 50±10% relative humidity. Cut corn stems were used for feeding of the larvae. Between examined linear models, Ikemoto and Takai model was estimated thermal constant and lower temperature threshold for development of S.cretica more precisely than Degreedays model. Based on the estimations of Ikemoto and Takai linear model, lower temperature threshold of egg, larva, pupa and overall immature stages of S. cretica were 13.97, 13., 12.57 and 13.27 ºC respectively, and thermal requirements were 68.44, 328.73, 140.16 and 537.43 degreedays for above mentioned immature stages, respectively.