8th of September 2009
Book review: Viruses in Orchids
N. Inouye
Orchids have become more and more popular in the last decades, so much so that even a useful (though Dutch) search-and-find website (orchidee.startpagina.nl) exists for orchids. Simultaneously the problems with virus diseases have increased, particularly due to the vegetative multiplication of the crop and the relatively long growing period of the plants in greenhouses or on windowsills. The Japanese expert in the field of orchid viruses, Dr Narinobe Inouye, published in 2001 a book on virus problems, in Japanese. This, however, is not a very accessible language in general. Therefore the recent translation of the book into English on the initiative of plant virologists associated with Naktuinbouw, is warmly welcomed.
The book deals with the aspects of orchid viruses mentioned in the subtitle, in four chapters.
In the first chapter the symptoms caused by viruses in various orchid species and varieties are described. This is important as such disease symptoms may indicate that a plant has a disease problem and often also which virus is involved: symptoms may be characteristic of certain viruses.
The various types of symptoms have extensively been described per virus and the terminology has been introduced. Most descriptive, however, are the many clear pictures (209 items), which give a clear illustration and which can help the grower or hobbyist in recognizing virus problems.
The second chapter treats the research that can be done in greenhouse and laboratory in order to answer two questions: 1. which plants of this lot are infected (by a virus)? and 2. which virus(es) caused the infection?
In this chapter many virological methods are reviewed in brief, although in quite some places probably too brief. It is also possible that occasionally information is “lost in translation”. Thus, a reader who has not been trained as a plant virologist may feel puzzled about the necessity and background of some of the described techniques or the line of thought followed. Such a reader might consult a book which contains more detailed information on plant virological methods (see for instance reference underneath).
Chapter 3 deals with the different ways in which viruses can be introduced, maintained and spread in orchids. Three systems are most important: introduction with infected planting material, transmission by stabbing insects and by nematodes, and contamination by or from all kinds of materials used in nursing and harvesting. The last includes contaminated tools, water (either for watering or for washing), various substrates and the hands of the grower.
Prevention of infections by viruses and their spread is then discussed: it will be clear that control of vectors and sanitary measures can do the job. Sanitary measures cover disinfection of all employed materials and tools, but also adjustment of the organisation of the work and of the environment of the plants. The starting grower or hobbyist reading this chapter will be aghast: this is hopeless, viruses are everywhere, one cannot see them and plants can very easily be contaminated and infected. One should then realise that many of the necessary measures can be included in routine schemes, which simplifies the whole matter.
The fourth and last chapter can be considered as a bonus. It contains:
● A rather general explanation of the properties of plant viruses;
● Per orchid-infecting virus: a description of all kinds of virus properties, either intrinsic (of the virus particles) or pathogenic;
● A review of the history of the research on orchid viruses.
The last parts of the book are four tables in appendices and a list of references. The tables give a list of all viruses found and described in orchids, with the properties of their particles, the orchid species they infect and their vectors.
This book contains much valuable information for orchid growers and orchid hobbyists, who experience virus problems in their crop or favourite plants, respectively.
Reference:
J. Dijkstra & C.P. de Jager (1998). Practical Plant Virology; Protocols and Exercises. Springer Verlag, Berlin, Heidelberg. 459 pp. ISBN 3-540-63759-1. Google (exact word combination) < J Dijkstra C P de Jager>
author: C.P. de Jager
source: Naktuinbouw