Compatibility of different strains of Steinernema spp. and Heterorhabditis spp. against tobacco caterpillar , Spodoptera litura

Abstract

The experiments were conducted under laboratory, Department of Nematology, CCS HAU, Hisar during the month of September-October, 2016-17. The virulence of five strains of Steinernema abbasi and two Heterorhabditis indica were evaluated against Spodoptera litura in four doses (5, 10, 20 and 40IJs/insect larvae) under in vitro conditions. As far as effect of different IJs is concerned, the significant mortality in larvae started at 5IJs/insect larvae However, nearly 50 per cent mortality of the larvae was observed at an inoculum level of 10IJs per larva after 24h. Among all the isolates of EPNs, S. abbasi isolate HAR-EPN-Sa-3 was highly virulent against S. litura. In case of H. indica, isolate HAR-EPN-Hi-2 was highly virulent and HAR-EPN-Hi-1 recorded the least virulence against S. litura. Laboratory studies revealed that S. abbasi in combination with H. indica had more virulence than S. abbasi and H. indica when applied alone. After 72 and 96h, both (H+S) caused 97.3 and 99.7 percent mortality. There was a mean death of 39.7 per cent and at 20IJs, 73.7 per cent mortality of S. litura could be recorded.