Abstract
A colony of Nilaparvata lugens, designated as K8, was formed by successive selection from infective and uninfective insects after four generations of acquisition feeding. Subsequent trasmission tests indicated 71% transmission for the selected infective insects, 21% for the selected uninfective, and 43% for the nonselected original colony. Ten colonies of N. lugens, collected from different localities in Japan and in different years, were divided into two groups which were tested for transmission rates with two replicates using different virus source plants. The original K8 colony was used as the control in all tests. The transmission rates varied from 8% to 46% (K8 : 50%) and from 1% to 19% (K8 : 21%) in the first and the second groups, respectively, which showed the least variations in the replicates of the same colony.
