Population growth of defoliator Cricula trifenestrata Helfer (Lepidoptera: Saturniidae) infesting Mangifera indica in terai region of West Bengal, India

The population growth parameters of Cricula trifenestrata Helfer (Lepidoptera: Saturniidae) infesting Mangifera indica differed significantly in different generations. The larval period was longer in generations completed during January to May (43.84 ± 1.48 to 42.59 ± 1.11 days). In May-October generation the pupal (88.20 ± 2.42 and 92.20 ± 2.30 days for male and female) and pre-adult period (136.89 ± 3.21 and 140.47 ± 3.04 days for male and female) were longest. The highest adult emergence, net reproductive rate and potential fecundity of adult of generation completed in October-January (48.14 ± 1.54%, 4.18 ± 0.18/♀ and 31.33 ± 0.86/♀) suggested more populations in January. The lowest net reproductive rate and potential fecundity of adult of March-May generation (2.86 ± 0.18/♀ and 23.97 ± 0.79/♀) suggested declined level of population in May to October. The lowest intrinsic rate of population increase (0.007 ± 0.0001♀eggs/♀/day) and longer mean generation (140.95 ± 3.30 days) and doubling time (93.37 ± 2.07 days) suggested May-October generation as the most unsuitable for population growth of C. trifenestrata, so, control measure should be taken during the period to improve the mango plant vigour for better yield.