稻褐飞虱致害性变异的研究

 研究了杭州褐飞虱田间种群在抗虫品种ASD7上强迫饲养多代后致害性的变化。结果表明，不同致害性的群体，在ASD7上饲养4代后，均可转变成能为害ASD7的ASD7种群。反之，在无抗性胁迫的感性品种TN1上连续饲养7代，ASD7种群对ASD7的致害性逐渐减弱，最终退化为TN1种群。这表明褐飞虱的致害性是可变异的，水稻品种抗、感虫特性是其转化的诱因。

Virulent Shift in Populations of Nilaparvata lugens (Homptera: Delphacidae)

The shift of virulence in ASD7 of rice brown planthopper from field and laboratory was studied. The resultsshowed that the field populations with different virulence, of which the virulence was determined by the amount of honeydewexcreted on ASD7, can shift to ASD7 population after rearing four generations on ASD7 respectively. On the contrary, thevirulence of ASD7 population became weak gradually during rearing on TN1. After seven generations rearing on TN1, ASD7population degenerated into TN1 population. It is suggested that virulence of rice brown planthopper was variable and thecharacter of variety resistant or susceptible to insect was the exterior factor of virulent shift.