Changing status of diapause in Zygogramma bicolorata Pallister in North India

The changing status of diapause in Zygogramma bicolorata was studied during winter. The eggs, grubs and mating pairs of the beetle were seen on the Parthenium hysterophorus on various sites. Field collected eggs hatched between 80–93% at 26 ± 1°C and 60 ± 5% R.H. as against 70–85% under natural weather in winter. No appreciable difference was observed with regards to incubation period, grub period, pupal period, as well as the extent of pupation and emergence. Beetles collected from the field continued to lay fertile eggs without any signs of facultative diapause. The beetle showed no obligatory diapause. Field observations carried out at Jammu, Jabalpur, Dehradun, Haridwar and Ghaziabad conformed that beetles were acclimatized as 7–39 eggs, 0–28 grubs and 3–19 adults were noticed in the fields at different sites.