Field life tables and key mortality factors of Pieris brassicae (Linnaeus) infesting cauliflower (Brassica oleracea var. botrytis)

Abstract

Abstract To investigate the key mortality factors of Pieris brassicae (Linnaeus) on cauliflower (Brassica oleracea var. botrytis), a field study was conducted on the field life table during 2021-22 at the research farm of the Punjab Agricultural University, Ludhiana, Punjab, India. Among biotic factors, Cotesia glomerata, Beauveria bassiana (Bals.), NPV, Bacillus thuringiensis (Berliner) were the main causes of mortality. Other unknown factors (temperature, rainfall, relative humidity, etc.) also contrived slight decline to all the immature stages of P. brassicae. Results revealed that the egg stage was affected due to unknown factors, whereas early larval instar stage (I-III) was the most sensitive followed by the late larval instar stage and pupal stage. The trend index was positive during both seasons 16.91 (main season), and 19.17 (late season), indicating that population of P. brassicae increases in the following season. Similar trend was observed in generation survival i.e., 0.39 (main season) and 0.32 (late season). In this study, a range of biotic factors was identified which could help to manage the pest at its early stages and the potential to be used as an integral component of integrated pest management of P. brassicae in cauliflower.