Effect of different temperature regime on biology and food utilization of tobacco leaf eating caterpillar (Spodoptera litura F.) on sunflower (Helianthus annuus L.) under laboratory conditions
A Rama Devi and S Jha
The experiment was conducted at laboratory of Plant Health Clinic, Directorate of Research, Bidhan Chandra Krishi Vishwavidyala (BCKV). The larvae of Spodoptera litura were reared at 20, 25 and 300C with RH 75±5% on sunflower. Basic growth parameters like larval period, length, width, consumption index (C.I.), average digestibility (A.D.), efficiency of conversion of ingested food (E.C.I.) and efficiency of conversion of digested food (E.C.D.) were computed to understand the growth behaviour at the mentioned temperature regimes. At 200C it took longer time to develop than 25 and 300C, whereas, maximum length and width were recorded at 300C in last instar. The larval period was 40.20±2.59 days at 20°C, 23.60±1.52 days at 25°C and 15±1.22 days at 30°C. The pre-pupal and pupal periods were 2.80±0.45 and 6.80±0.45 days at 20°C; 2.20±0.45 and 5.60±0.55 days at 25°C; 1.80±0.45 and 4.80±0.84 days at 30°C. The total developmental period from egg to adult emergence were 57.80±2.78 days at 20°C, 38.60±1.81 days at 25°C and 28.00±2.26 days at 30°C respectively. Food consumption increased with rise in temperature, first instar larvae showed high consumption index, which gradually decreased with larval age. Average digestibility for entire larval life decreased with larval age, but at all temperature regimes fifth and sixth instars digested more leaves than preceding instar. The efficiency of conversion of ingested food and efficiency of conversion of digested food values increased not only with advanced larval instar, but also with rise in temperature.
A Rama Devi, S Jha. Effect of different temperature regime on biology and food utilization of tobacco leaf eating caterpillar (Spodoptera litura F.) on sunflower (Helianthus annuus L.) under laboratory conditions. J Entomol Zool Stud 2017;5(5):602-606.