Effect of Temperature on Life Cycle of Spodoptera frugiperda under Laboratory Conditions

Fall armyworm, Spodoptera frugiperda (Diptera:Lepidoptera) is a destructive pest of agricultural crops especially maize in many countries including Pakistan. The environmental factors like temperature play significant role in the growth and development of insect pests. It is very important to know the proper knowledge about effect of temperature on the development of Spodoptera frugiperda before managing this pest. For this purpose, the current study was conducted to check the effect of temperature (20 and 26◦C) on the life cycle of S. frugiperda under laboratory conditions. The results showed that the developmental times of all stages (eggs, larvae and pupae) were inversely related to temperature. The incubation period of eggs was 4.01±0.00b and 2.00±0.00b at 20 and 26◦C, respectively. The development time of first, second, third, fourth, fifth and sixth larval instar was 3.51±0.10b, 3.04±0.15b, 2.33±0.10b, 2.97±0.14b, 3.45±0.19b and 4.99± 0.22b, respectively at 20◦C while 2.77±0.13c, 2.89±0.20bc, 2.09±0.12bc, 2.22±0.17bc, 2.90±0.23c and 3.56±0.19b, respectively at 26◦C. The time of growth and development was increased at low temperature while reduced at high temperature. The food consumption rate and molting period of larvae can increase at high temperature for complete their growth and development. The current study concluded that environmental factors like temperature are highly effect the insect pests morphology and biology.