我国稻螟灾害的现状及损失估计

我国稻螟为害的确切记载始于 1 0 2 2年。 2 0世纪 5 0年代中期以前 ,以二化螟Chilosuppressalis(Walker)为害为主。此后十几年中 ,三化螟Tryporyzaincertulas(Walker)普遍大发生。 70年代 ,我国螟害轻微。 1 993年 ,二化螟急剧回升 ,三化螟也随之回升。 1 996年 2种稻螟大发生 ,此后连年暴发成灾。目前我国螟灾的主要特点是虫口密度高、受害范围广、受害程度重、持续时间长、经济损失大。首要螟灾区是沿江稻区 ,二化螟和三化螟分别约占 2 3和 1 3。全国年发面积约 1 5 0 0万hm2 ,防治约 3 80 0万hm2 次。该文首次估计年防治代价约 45 7～ 60亿元 ,残虫造成作物损失近 65亿元 ,总经济损失约 1 1 5亿元。由此可见 ,当前稻螟已取代稻飞虱、棉铃虫成为影响我国国计民生的头号害虫。

Pest status and loss assessment of crop damage caused by the rice borers, Chilo suppressalis and Tryporyza incertulas in China

This paper gives an overview on the history, pest status and damage assessment of the rice stem borer, Chilo suppressalis (Walker) and yellow rice borer, Tryporyza incertulas (Walker) in China. The first undoubted infestation and damage caused by these species was recorded in 1 022 during the Song Dynasty. The rice stem borer was dominant among these two species prior to 1956. However, the yellow rice borer increased significantly from 1956～1970. In the 1970's, the damage caused by these two borers was trifling. However, the population density of both pests had increased markedly by 1993 and outbreaks of both occurred in 1996. Since then, both species have caused disasterous crop damage every year. The present situation is characterized by a high density level, large area of infestation, severe crop damage, long time duration and huge economic loss. The most serious damage is found in the rice belt of Yangtze River Valley where about 2/3 of the damage is caused by the rice stem borer and 1/3 by the yellow rice borer. There is an estimated 15 million hectares per year infested with these pests and 38 million hectares that are treated with pesticides. We estimate that these pests cause a gross loss of 11.5 billion yuan (1 US dollar=8.27 yuan), consisting of 5 billion yuan control cost and 6.5 billion yuan of crop yield loss, each year. The authors believe that these two borers have become the No. 1 crop pests in China after the plant hoppers and cotton bollworm, Helicoverpa armigera (Hübner).