白背飞虱Sogatella furcifera(Horváth)是我市早、中稻上的主要害虫,1975—83年我们对此虫进行了研究,整理出以当地一代若虫稳定期田间加权平均虫量为基数预测下一代(主害代)发生趋势的方法,具有较好的效果。现将结果整理如下。 一、“主害代”候最高虫量出现期 据几年来的观察,我市于每年5月下旬初见长翅型成虫,约经30天左右,于6月下旬至7月上旬繁殖一代,并出现第一代若虫羽化盛 Sogatella furcifera (Horváth) is a major pest on early rice and medium rice in our city. From 1975 to 1983, we studied the insects, and sorted out the next generation based on the weighted average population of field-born nymphs (The main victim generation) the trend of the method has a good effect. The results are now organized as follows. According to the observation over the past few years, the city first saw the long-winged adult worms in late May each year. After about 30 days, the breeding breed in late June to early July, And the emergence of the first generation nymph plumage