马铃薯二十八星瓢虫是我区马铃薯上常发性的、为害较大的害虫。为了掌握它的发生规律,为防治提供依据,我们从1978年开始进行了系统观察,现将资料整理如下。一、发生规律1.发生历期1978年6月在室内自然温湿度条件下观察,日平均温度为23.9℃,日平均相对湿度为68%。①卵期共观察258粒。孵化时间为5—7天,6天的最多,平均为6天。孵化率平均51.2%。田间卵的孵化率比较低,1978—1983年观察仅为21.1%。②幼虫期二十八星瓢虫的幼虫一生蜕4次皮,为4龄。第一龄幼虫为4.99±1.4天;第二龄幼虫为4.26±1.46天;第三龄幼 Potato twenty-eight ladybug is a potato in our region often, more harmful pests. In order to grasp the law of its occurrence and to provide the basis for prevention and treatment, we have systematically observed it since 1978, and now the data are organized as follows. First, the occurrence of law 1. Occurs in June 1978 under the conditions of natural indoor temperature and humidity observed, the average daily temperature of 23.9 ℃, the average daily relative humidity of 68%. ① observed a total of 258 eggs. Incubation time is 5-7 days, up to 6 days, an average of 6 days. Incubation rate average 51.2%. The hatching rate of field eggs was relatively low, with only 21.1% observed in 1978-1983. ② larvae twenty-eight ladybug larvae life shed 4 times the skin, for the fourth instar. The first instar larvae were 4.99 ± 1.4 days; the second instar larvae were 4.26 ± 1.46 days; the third instar ones were young