Population Dynamics of the Cabbage Butterfly [Pieris brassicae L. (Lepidoptera: Pieridae)] on Broccoli in the Western Himalayan Region

The present investigation was carried out at the Vegetable Research Farm of the Department of Vegetable Science, College of Horticulture, VCSG Uttarakhand University of Horticulture and Forestry, Bharsar, Pauri Garhwal, Uttarakhand, to study the population dynamics of cabbage butterfly on broccoli. The standard weeks were considered as treatments. The experiment was conducted in two cropping seasons with twelve treatments and three replications. The number of eggs, larvae, number of pupae and adults of the cabbage butterfly were visually recorded at each standard week by correlating with weather parameters in two cropping seasons. During the first season (17th– 28th standard week) the eggs of the cabbage butterfly increased gradually and reached a peak level of 11.49 eggs at 24th standard week, 12.83 larvae at 23rd standard week, 10.49 pupae at 24th standard week and 1.34 adults at 23rd standard week. In the second season (37th – 48th standard week), the eggs laid by the Cabbage white butterfly increased gradually and reached a peak level of 10.49 eggs in 44th standard week, 10.56 larvae at 40th standard week, 8.48 pupa at 48th standard week and 0.48 adult at 48th standard week. The decline trend was observed due to the fall of optimum weather conditions for the cabbage butterfly.