论文部分内容阅读
黑龙港流域的黄骅、盐山、孟村、海兴、青县、中捷、南大港等市、县、农场,每年种植向日葵的总面积都在25万亩左右。因受第四代棉铃虫的危害,历年一般都减产10—20%,严重年减产达30%。由于除治不及时、不彻底,不仅年年遗留下大量残虫,并给下一年棉田开展除治工作带来很大困难。四代棉铃虫在我市发生发展的规律一般是:8月下旬成虫在向
The total area of sunflower cultivated in Huanghua, Yanshan, Mengcun, Haixing, Qingxian, Zhongjie, Nantang and other cities, counties and farms in Heilongjiang River Basin is about 250,000 mu each year. Due to the damage caused by the fourth generation of cotton bollworm, the average annual production has been reduced by 10-20%, a serious annual reduction of 30%. Since the rule of cure is not timely and incomplete, it not only leaves a large number of plant diseases year after year, but also brings great difficulties to the drastic elimination of cotton fields in the next year. Four generations of cotton bollworm in the development of the city’s law is generally: in late August in adults