1959 Volume 3 Issue 1 Pages 49-55
The green rice leafhopper, a pest of the rice plant, Nephotettix bipunctatus cincticeps UHLER, was reared under a long photoperiod and a short photoperiod at 20°C and 30°C, and the following results were obtained.
1. At 20°C a clear elongation of the duration of the 4th and the 5th larval stages was found under a short photoperiod of 8hr, while under a long photopeeriod of ca. 14hr 30min a normal development was found.
2. At 30°C no effect of the photoperiod on the development was found.
3. At alternating temperature between 10°C for 16hr and 30°C for 8hr per day, much clear elongation of the developmental period was found if the larvae were kept in darkness at the phase of 10°C. On the other hand, normal development was obtained under permanent illumination.
4. The larvae in the arrest of development were induced to develop promptly if they were put in a long photoperiod even at the same temperature of 20°C. High temperature, such as 30°C is also effective without regard to the photoperiod in which the larvae are to be put, though it is more effective under a long photoperiod than under a short one.
5. The development of the larvae in the state of arrest is induced to normal if the larvae are chilled at 10°C for more than 50 days.
6. It was discussed whether or not the arrest of development can be considered as a diapause. As affirmative characters the followings are concerned, that is, the arrest of development is induced by a short photoperiod and the arrest is completed by chilling for appropriate durations. As negative characters, larvae in the arresting state need succulent food without which they soon die and coldhardiness at 0°C is low compared with those characters in the small brown planthopper.
