A reproduction of a Thesis in partial fulfillment of the degree of Master of Science at the University of Auckland, New Zealand 1988. A study of 3 virus diseases affecting Vanilla fragrans in the Kingdom of Tonga. The global Vanilla industry is worth billions of dollars. Natural Vanilla, however, only make up a small percentage of the total. Synthetic 'vannaline'/ ' vanilla essence' is by far the most common.It does make natural Vanilla a very valuable commodity, second only to saffron in price. Cured Vanilla beans of the best quality can fetch prices in excess of $US200 per kilo in average trading times. Therefore, the Vanilla industry in producing countries is a valuable asset for its communities.This book is about a study to find control measures for a virus destroying Vanilla plants. Two other viruses were also investigated. The information is in 'Scientific format' and is worth its weight in gold.Any Scientific Library, Vanilla Producing Companies, Vanilla Exporters and Importers around the world should have a copy of this book in its collection of valuable literature assets. All pictures are in color so it is very, very useful for research and decision making.