Life table and biotic potentialof Maruca vitrata (Geyer) (Lepidoptera: Crambidae) on chickpea artificial diet
Shwetha Surpur, Suhas Yelshetty, AG Sreenivas and BV Patil
Life table studies of Maruca vitrata (Geyer) carried out on chickpea artificial diet under controlled environmental condition of 26 ± 1°C temperature with a photoperiod of 14:10 L:D and 60 ± 10% relative humidity at Agriculture Research Station, Kalaburagi, during 2015-16. Results revealed that high mortality was observed at egg, 1st instar and pupal stages which indicated minimum survival fraction at these stages and maximum at 4th and 6th larval instars. The number that survived from egg to adults was 78 individuals. Investigation on life fecundity tables and age specific distribution revealed that the expectancy of newly laid eggs was 332.43. The survival of different life stages of Maruca vitrata on pigeonpea diet was found to be 3, 14 and 8 days in egg, larval and pupal stages, respectively. The number that survived from egg to adults was 78 individuals. The main length of generation was (Tc) 31.23 days and (T) 31.35 days. The intrinsic rate of increase was examined to be 0.12females/female/day, repetitively. Under sufficient food supply, the population of Maruca vitrata increased with and infinitesimal rate (rm) of 0.12 and finite rate (λ) 1.14 females/female/day. A generation was completed in 31.23 days. The population of M. vitrata was capable to multiply 2.44 times/week under the given set of conditions. The population on reaching a stable age distribution comprised approximately 42.92% of immature stage. Age distribution of this pest on chick pea manifested that eggs and larvae contributed the highest to the population of stable age, where as the contribution of pupa was negligible.