Applicability of the Temperature-Sum Rule in Estimating the Emergence Time of the Overwintering Population of the Green Rice Leafhopper, Nephotettix cincticep UHLER (Hemiptera

• Published in: Applied entomology and zoology Vol. 6; no. 1; p. 1
• Main Author: HOKYO, Nobuhiko
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer Nature B.V 01.01.1971
• ISSN: 0003-6862; 1347-605X

Applicability of the temperatuure-sum rule was examined for the period when the nymphal development of overwintering population of green rice leafhopper, Nephotettix cincticeps UHLER, proceeded under daily mean temperatures for below the developmental zero point of this insect, i.e., 13.3°C (KISIMOTO. 1959c). Days when daily maximum temperature exceeded 12.0°C were picked up from January to the 50% date of adult emergence and the cumulative day-degree were calculated from the portions of daily thermo-curves above 12.0°C. The cumulative day-degrees from January to the 50% moulting date of the fourth instar which occurred usually in early or middle March fluctuated from 5 to 15 day-degrees. On the other hand, the cumulative day-degrees from the 50% moulting date of the fourth instar to that of the fifth instar (=50% data of adult emergence) took a fixed value of about 50 day-degrees. Therefore, the temperature-sum rule is useful in estimating the 50% date of adult emergence by knowing the date when the cumulative day-degrees from the 50% moulting date of the fourth instar (or roughly from middle March) reach a value of about 50.