The effect of temperature on growth and development of Thrips tabaci Lindeman was studied on Bt cotton at different constant temperature (25, 30 and 35°C) and 60 per cent relative humidity. Among all the three constant temperatures, significantly the lowest duration (days) of incubation period (2.39), 1st instar (2.29) and 2nd instar (3.03) nymphs, total nymphal period (5.10), pre-pupal period (1.28), pupal period (1.85), total development period (10.00), adult longevity (8.21) and total life cycle (18.13) were observed at 35°C, and these were highest (4.58, 4.23, 5.78, 9.93, 2.12, 3.21 and 19.56, 22.19 and 41.72, respectively) at 25°C. Maximum fecundity-cum-viability (21.70 nymphs/female) and nymphal survival (78%) were observed at 25°C, respectively and these were the minimum at 35°C i.e. 7.80 nymphs per female and 34 per cent, respectively. Maximum growth index was observed at 30°C and it was minimum at 35°C i.e. 7.92 and 6.70, respectively. It can be concluded that with the increase in temperature from 25 to 35°C there was significant decrease in the duration of various developmental parameters, adult life parameters, total life cycle and per cent survival of T. tabaci. Optimum temperature for the growth of T. tabaci is 30°C as growth index was maximum at this temperature.

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