Facultative diapause behavior of pink bollworm, PectinophoragossypiellaSaunders (Lepidoptera: Gelechiidae) in South Indian populations

Background The pink bollworm (PBW) of cotton, Pectinophora gossypiella Saunders is one of the serious pests in the Bt cotton era of India. Development of resistance to insecticides and behavioral adaptations are the main factors attributed for its severity. The North Indian populations of PBW are reported to be undergoing facultative diapause, whereas, no clear reports are available on the diapause pattern of South Indian populations. Hence, the diapause behavior of south Indian populations was studied at the UAS, Raichur, Karnataka. Results Populations collected from different parts of Karnataka, South India exhibited diapause behavior though the intensity varied. A significant variation in the morphometry of larval, pupal and adult populations of diapause and non-diapausing group was observed. Similar variation was also noticed in the biochemical parameters. Higher levels of amino acids, fats, proteins, and nitrogen were recorded in diapausing population compared to non-diapause population. Enzyme activities such as LDH, AP, GPT, and GOT varied between diapause and non-diapause population. The diapause behavior in South Indian PBW population was initiated from February, peaked in March, and ceased by May. Most larvae terminated diapause in November, coinciding with peak boll formation in cotton. Conclusion South Indian population of cotton pink bollworm exhibit facultative diapasue behavior. A clear cut morphological and physiological differentiation was recorded between diapusing and non-diapasuing individuals of the species. An in-depth study on the factors influencing the initiation, regulation and termination of diapasue in PBW need to be carried out.