Diseases and insect pests which occur in hybrid rice in China are similar to those which occur in inbred rice. Major diseases and insect pests are blast ( Pyricularia oryzae ), sheath blight ( Thanatephorus cucumeris [ Rhizoctonia solani ]), bacterial blight ( Xanthomonas oryzae ), stem borer, rice planthopper, and leaffolder ( Cnaphalocrocis medinalis ). As the characteristics and cultural practices of hybrid rice are different from those of inbred rice, the occurrence of diseases and insect pests in hybrid rice has its own distinguishing features. In southern China, were high-yielding hybrid rice is the major crop, the strategy for disease and insect control involves integrated pest management (IPM) as the main method and artificial regulation as the subordinate one. The key technical measures include the develop ment of resistant varieties, cultural control, protection and use of natural enemies,and rational use of chemicals. In 1986-90, the above measures were undertaken in six provinces (Sichuan, Jiangsu, Zhejiang, Hubei, Hunan, and Guangdong), the area of ricefields where IPM was practiced reached 6.60 million ha, and the economic,social, and ecological benefits obtained were very significant. The direct economic benefit was worth US$0.1-0.2 billion.
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