Beet armyworm Spodoptera exigua (Hubner): A newly emerging pest of Egyptian clover in Punjab

Abstract

Studies on population dynamics of Thysanoplusia oricalcea, Helicoverpa armigera and Spodoptera exigua were carried out on berseem. All the three lepidopterans were prevelant throughout the season but H. armigera population was negligible during Feburary-March and increased in April. Mean larval population of T. oricalcea, S. exigua and H. armigera was 2.33, 0.88 and 1.13 larvae/ m2 at PAU, Ludhiana and 0.83, 3.71 and 0.92 larvae/m2 at RRS, Gurdaspur. Investigation on biological characteristics along with molecular phylogeny of beet armyworm S. exigua were undertaken keeping in view presence of damaging population of pest on the berseem at two locations (Ludhiana and Gurdaspur) in Punjab. The study revealed that the average egg, larval, pupal, adult male and adult female period were 2.4 ± 0.55, 18.6 ± 1.7, 8.4 ± 1.14, 6.8 ± 0.8 and 7.6 ± 0.9 days, respectively. The average life cycle was completed in 29.4 ± 1.5 days and average fecundity was 241.2 ± 30 eggs per female. On the basis of mitochondrial sequences, Ludhiana population of S. exigua was almost similar to all The Netherlands populations and one of the German populations.