The biological control of plant diseases : proceedings of the International Seminar "Biological Control of Plant Diseases and Virus Vectors"; sponsored by the Food and Fertilizer Technology Center for the ASPAC region, National Agriculture Research Center (NARC), Japan, National Institute of Agro-Environmental Sciences, Japan held in Tsukuba, Japan, September 17-21, 1990 . (FFTC book series, 1991)