我省北、中部地区,近年来随着兴修水利,特别是引黄灌溉工程的扩大,水稻面积迅速增加。但由于水稻孕穗至抽穗灌浆阶段最易受病虫侵害,而麦茬水稻该阶段正是外来菌源、虫源迁入期,加之推广了不抗病虫的水稻品种,用种量大(每亩250～400斤) In the northern and central regions of our province, the area of ​​rice has rapidly increased with the expansion of water conservancy projects especially in the Yellow River Diversion Project in recent years. However, since rice is most susceptible to pests and diseases at the stage of booting from ear to ear, the stage of wheat stubble rice is immigrating from source and source of insects, and the promotion of non-pest-resistant rice varieties, 250 ~ 400 pounds)