浙江省双季稻区稻水象甲致害种群的形成

ON THE FORMATION OF DESTRUCTIVE POPULATION OF RICE WATER WEEVIL IN DOUBLE RICE CROPPING AREA OF ZHEJIANG PROVINCE,CHINA

1994～1996年对浙江省双季稻区稻水象甲Lissorhoptrus oryzophilus Kuschel春季迁飞的系统研究表明,以飞行肌发育起点温度13.8℃以上的有效积温结合当地、当日起飞时段的天气情况预测越冬代成虫的迁入峰期是完全可行的。越冬成虫的第1波下迁一般出现在有效积温达70～90日度时,主迁峰则视天气条件出现在积温达90～140日度时。越冬代成虫大量起飞的最适条件是气温>20℃且无风或微风,故起飞一般始于16∶00左右,在气温低于20℃时终止。早春及4月上中旬的降水可影响飞行肌的发育速率,从而影响第1波下迁的时间;4月下旬和5月上旬的降水则影响主迁峰的出现时间。

There are two generations of rice water weevil (RWW) Lissorhoptrus ory-zophilus Kuschel per year in the double rice cropping area of Zhejiang Province, but only the larvae of first generation damage early rice. The results of studies on spring migration of RWW from 1994 to 1996 indicated that the effective temperature constant (ETC, measured by day degrees) over 13. 8 C , the developmental zero of its flight muscle, and local weather conditions at the time it takes off are quite available for predicting the immigration peak time of overwintering generation adult. The first immigration wave will generally occur in the ETC range from 70 to 90 day degrees, and the immigration peak will occur in a wider ETC range from 90 to 140 day degrees, depends on the weather condition. The optimum conditions for spring immigration of RWW are rather high temperature (>20C) and calm or breeze of wind, so its takeoff will generally begin at 16:00 and stop at the time the air temperature drops under 20 C. The precipitation in early spring and early and middle April can reduce the development rate of flight muscle and delay the occurrence of first immigration wave, and the occurrence of immigration peak is usually determined by the rainfall in April and early May.