Introductory papers address current principles and practices of plant virus taxonomy. The next section treats aspects of virus transmission and transport. E.g., Khan (National Botanical Research Institute, Lucknow, India) and Dijkstra, a plant virologist formerly at Wageningen Agricultural U. (the Netherlands), contribute papers on the characteristic features of virus transmission by nematodes, fungal vectors, and seeds. Sets of contributions then discuss the molecular biology of RNA and DNA viruses. Coverage of methods in molecular virology, such as novel applications of DNA polymerase ( journal's 1989 molecule of the year), conclude the volume. Includes supporting illustrations and reference tables. Annotation c. Book News, Inc., Portland, OR