Comparative studies on biology of Chelonus blackburni (Cameron) (Hymenoptera:Braconidae) on Phthorimaea operculella (Zeller) and Corcyra cephalonica (Stainton) under laboratory conditions

Chelonus blackburni (Cameron) that parasitizes eggs of potato tuber moth is widely distributed and occurs commonly in potato fields throughout the country. Studies on its biology and ovipositional performance were carried out on both hosts i.e. Phthorimaea operculella and Corcyra cephalonica in laboratory conditions. Average number of eggs laid per female was found to be 210.9 ± 16.62 on P. operculella and 118.4 ± 7.49 on C. cephalonica. Incubation period of the parasitoid on P. operculella was 24.5 ± 1.62 hours on an average, while on C. cephalonica, it was found as 25.2 ± 1.33 hours. Total larval duration was 14.5 days and 19.2 days on P. operculella and C. cephalonica, respectively. Pupal period was 10.6 ± 0.70 days on P. operculella, whereas it was slightly higher on C. cephalonica (13 ± 0.57 days). The average life span was observed to be 6.8 days on P. operculella and 7.7 days on C. cephalonica.