author(s)
Pradeep Kumar Dalal and Ramesh Arora

abstract
The effect of various alternating temperatures on the development rate of immature stages of H. armigera (Hübner) on tomato crop was studied during 2013-14. Immature stages were exposed to multiple alternating temperatures (Max: Min˚C) varying from 25:10 to 30:16 ˚C. Development rates of all immature stages enhanced with the rise in alternating temperatures. Egg, larval, pupal, and total development rate of H. armigera were in the range of 0.24-0.34, 0.021-0.031, 0.043-0.077 and 0.013-0.021 d^-1, respectively. These development rates were fitted into three non-linear models viz. Lactin-2, Briere-1, and Briere-2 models which predicted favourable temperature ranges for H. armigera total immature period development that was 11.7-53.7 °C, 8.3-34.0 °C and 9.4-42.7 °C, respectively. Both Briere-1 and Briere-2 estimation for total immature period were better than Lactin-2. In contrast, Lactin-2 model was most reliable in estimating the favourable temperature range for all stages of H. armigera development. H. armigera attained maximum development rate at 35.4, 28.2 and 30.4 °C as per Lactin-2, Briere-1, and Briere-2 models, respectively. The present study is crucial in predicting the occurrence of H. armigera in the tomato field and will assist in the need-based application of control measures under integrated pest management.