INFLUENCE OF TEMPERATURE ON SURVIVAL AND DEVELOPMENT OF HELICOVERPA ARMIGERA (HUBNER)Vijay Kumar and G.K. GrewalAbstract To determine the effect of temperature on survival and development of H. armigera five different temperatures (18, 21, 25, 29 and 31 0C) was investigated. The results showed that higher survivorship was recorded at 25 0C (35.00) followed by 29 0C (28.33) and 18 0C (13.15). The results also showed that the duration of development of H. armigera decreased as the temperature increased from 18 0C to 31 0C. About 100 per cent of mature larvae stopped pupating at 31 0C. The results indicated that the optimum growth temperature of H. armigera was about 25 0C. The percentages of larvae at first, second, third, fourth, fifth, prepupal, pupal stage different at the different temperatures. The percentage of first instar (41.66), 2nd instar (31.66), 3rd instar (31.66), 4th instar (31.66), 5th instar (31.66), prepupal stage (31.66) and pupa formation (31.66) was higher at 25 0C. However, the percentage of adult emergence was higher at 29 0C (25.00) followed by 25 0C (21.66). |