云南山区90％以上的钉螺和阳性钉螺分布在稻田（梯田）之中，而且主要分布于梯田高埂壁上。了解稻田阳性螺点的变化，探索其消长规律，对指导查螺和进行重点灭螺具有重要意义。为此，1992年5月至1995年3月，我们在云南巍山县中和行政村的中和铺自然村进行了稻田阳性螺点变化情 More than 90% of snails and positive snails in mountainous areas of Yunnan are distributed in paddy fields (terraced fields), and are mainly distributed on the high ridge walls of terraces. Knowing the change of the positive snail point in paddy fields and exploring its growth and declination rules is of great significance to guide snail hunting and key snail-killing. For this reason, from May 1992 to March 1995, we conducted a positive spiral change of paddy field in Zhonghepu Nature Village, Zhonghe Administrative Village, Weishan County, Yunnan Province