Field life tables and key mortality factors of Helicoverpa armigera infesting tomato (Solanum lycopersicon)

Abstract

Field life table studies of Helicoverpa armigera (Hübner) infesting tomato (Solanum lycopersicon L.) wereundertaken during 2018 and 2019 at research farm of Punjab Agricultural University, Ludhiana, Punjab. Key mortality factors observed in early and late larval instar groups were Campoletis chlorideae (Uchida), Beauveria bassiana (Bals.), HaNPV, Bacillus thuringiensis (Berliner), along with other unknown factors. The egg stage was the most vulnerable exhibiting the highest loss (32.0–91.0%) during main and spring season tomato crop followed by early larval stage (40.27–44.86%), late larval stage (35.84–40.95%), and pupal (24.45–29.23%) stage. Trend index was positive (4.54) on main season crop which showed that total mortality factors during this season were not effective in causing the pest decline and it was negative (0.22) on spring season crop which depicted that total mortality factors were more effective and the chances of increase in population during next season would be less. Generation survival was highest on main season crop (0.29) as compared to spring season (0.23) and indicated that maximum generation survival was in main season whereas, in spring season the generation survival was lower and contributed maximum towards mortality