Photoperiodic Responses in Two Local Populations of the Smaller Tea Tortrix, Adoxophyes orana FISCHER VON ROSLERSTAMM (Lepidoptera : Tortricidae)

Abstract

An experiment on the effects of short-day treatments on two local (Morioka ans Sakai) stocks of the smaller tea tortrix, Adoxophyes orana FISCHER VON ROSLERSTAMM was made at a temperature of 20°C, and a conspicuous difference was observed in the photoperiodec response between the local stocks. The larvae of the Morioka stock in an 8-hour photoperiod ceased their growth in the third instar. On the other hand, those of the Sakai stock continued their growth, though the growth rate decreased with the increasing duration of the shot-day treatment. This local variation in the mode of photoperiodic response seemed to be closely related to the different overwintering behaviours observed in tea plantations and apple orchards.