†Department of Zoology, Andhra University, Visakhapatnam - 530 003, Andhra Pradesh, India.
$SKR College for women, Rajahmundry - 533105, Andhra Pradesh, India.
Central Tobacco Research Institute, Rajahmundry - 533 105, Andhra Pradesh, India.
A study was conducted to evaluate the reaction of 36 accessions of wild Nicotiana species to Spodoptera litura (Fab.) through construction of age specific life tables, age specific fertility table of female and computation of various life parameters under laboratory conditions keeping only quality of food as limiting factor. Among the 36 accessions, S. litura could complete its life cycle only on Nicotiana glauca and N. debneyi. Though there was a very high mortality of neonate larvae on both these species as evidenced by survivorship (lx), the mortality was on a higher side in case of N. debneyi. Ninety eight per cent of the population of S. litura was comprised of egg and larval stages after attaining stable age distribution on these two species. The female survivorship was very low in the range of 0.03 and 0.04 on these species. There was no mortality of adult females during the entire period of oviposition in both the species. Potential fecundity (pf) and net reproductive rate (R0) of S. litura were three times higher on N. glauca than on N. debneyi. Mean generation time (Tc) was slightly longer (34.6 days) on N. debneyi than on N. glauca (32.5 days). Among the 34 species of Nicotiana on which S. litura could not complete its life cycle, N. noctiflora supported the growth of S. litura for the longest period of 32 days. Polyphenols, Nicotine, leaf surface waxes and density of glandular trichomes on the leaf were markedly high on the species that supported very poor growth of S. litura implicating their role in determining host suitability.
Wild Nicotiana, Spodoptera litura, life tables, host suitability
