云南稻纵卷叶螟的发生与种群消长特点

The occurrence characteristics and population dynamics of Cnaphalocrocis medianalis in Yunnan Province

2009—2012年,对滇西、滇西南、滇南、滇东南、滇东和滇东北6个稻区的稻纵卷叶螟Cnaphalocrocis medinalis Guenée种群发生特点进行了研究,结果表明:(1)云南主要稻区均没有采集到稻纵卷叶螟的各越冬虫态,表明云南稻区的稻纵卷叶螟早期虫源主要来自境外;(2)灯下虫源始见期在4月中旬到7月中旬,不同稻区的虫源迁入期变化较大,相差近3个月。滇西沧源和滇东南富宁虫源始见期最早,在4月中旬—5月下旬,滇西南勐海灯下始见期最晚,为6月上旬—7月中旬;(3)滇西、滇西南、滇东北和滇南为稻纵卷叶螟轻发生区,主要在中晚稻上发生危害,田间卷叶率在30%以下,田间发生量少于300头/667m2。滇东和滇东南为中等和重发生区,田间卷叶率在30%以上,高的达80%以上,田间虫量最高可达7 000头/667m2;(4)云南稻纵卷叶螟田间种群发生高峰期主要集中在5月下旬至9月下旬。滇东南高峰期为6月下—7月中旬,正值水稻孕穗期到抽穗开花期,应做好田间监测与防治工作。

The occurrence characteristics and population dynamics of Cnaphalocrocis medinalis Guen6e were investigated in six major rice growing areas; west, southwest, south, southeast, east and northeast Y unnan in 2009-2012. The results show that C. medianalis was not detected in Yunnan in winter, which indicates that early immigrants of this pest originate mainly from overseas. Second, first detection dates of immigrants ranged from mid-April to mid-July; a span of nearly 3 months. Immigration to the west and southeast occurred from mid-April to late-May, but immigration to the southwest occurred from early-June to mid-July. Third, the west, southwest, northeast and south of Yunnan had relatively low abundances of this pest, which mainly occurred in middle-late rice fields. The leaf roll rate was less 30% and adult population density 〈 300 adults/667m2. The eastern and southeastern rice growing areas experienced moderate to serious damage with leaf-roll rates exceeding 80% and adult densities of up to 7 000 adults/667m^2. Fourth, the adult population peak occurred mainly from late-May to late-September. In the southeast, which suffers serious damage, the peak of adult occurrence is from June to mid-July which when rice crops are most vulnerable to this pest. So, monitoring and prevention measures for the rice leaf roller are particularly essential in Yunnan＇ s southeast rice growing region.