1 Department of Entomology, CSK HPKV Palampur-176 062, Himachal Pradesh, India.
Growth rate of Phthorimaea operculella (Zeller) was studied by developing fertility schedules on potato leaves and tubers under laboratory conditions. The population of P. operculella multiplied 16.84–33.75 times over a generation time (T) of 25.58–47.06 days in different generations during February – October. The multiplication rate was lower during August–October in fifth and sixth generations with slightly higher generation times (35.39 – 47.07 days). The highest multiplication rate was recorded during June in third generation. The doubling time (DT) was also shortest (5.50 days) in June–July during third and fourth generations.
