Dear PBS members, Though I am not a professional pathologist, I am a passionate horticulturist and conservationist. Ben Zonneveld brings up a good point. Not all viruses reduce a plant's vigour nor are viruses responsible for many variegations (especially foliar) found in ornamental plants today. Some viruses are now essential to modern biological research methods. Still, there is so much that we do yet not know about the viruses that affect plants. Not only are many undescribed, but we also lack comprehensive data on the biology of all the species that have been isolated. There is much to learn about their full range of plant host families and information about in which plant genera viruses can specifically do harm. Research in microrganisms is more often than not prioritised by the concerns of medical science and food crop industries. My guess is that because most geophytes have no market value other than in trade as ornamentals, this is why there are comparatively less studies on symptomatic plant viruses that especially target ornamental crops. Nhu Nguyen and I have compiled all the data that we have found on the viruses that are recorded as affecting geophytes on the wiki. Please see: http://pacificbulbsociety.org/pbswiki/index.php/… It is true that viruses are just as much a part of nature as humans or our favourite bulb species are. Thus a goal of complete eradication of the problem viruses is not only highly unlikely but also possibly unnatural (though I realise that humans do act as a part of nature). In this age of massive habitat destruction, unprecedented extinctions and threats to plant life on this planet, including that of many of our beloved geophytes, our thinking on how we treat what we cultivate takes on new importance. Whether or not the material that we grow will ever be relevant to in situ conservation/re-introduction efforts, it is still very important to take care of our species and keep good records of their provenance as if they could be used for such efforts in the future. Collectively, what we choose to grow and how well we increase our species' by seed will determine what is available for the next generation of horticulturists to choose from for their gardens, particularly in the case of species that will go extinct in our lifetime or have become impossible to transport across international borders. When we spot features in our plants that seem as though they may be symptomatic of a virus, it is quite often very difficult to determine if our plants are indeed infected with a harmful virus. Lack of proper nutrients, adverse weather conditions, damage from sucking insects and phytotoxic reactions to chemicals may all mimic viral infection. How can we know for sure? Labs offer ELISA testing services to orchid growers for the most well known orchid viruses such as Cymbidium Mosaic Virus. All one must do is pay a small fee and send a tissue sample in the mail to have a definitive result. I have contacted many of these labs to see if they are set up to provide testing for some of the viruses that affect geophytes (see above link to the wiki page on virus for a list) but have not yet found any lab willing to test for these. I wish I could recommend a service. I heard that UC Davis may be able to do this but have not followed up on it. I have tested my orchid collection for infected plants and would love to be able to do this for my geophytes. Until then I keep an observant eye for symptoms, vectors and keep plants we've grown from seed separate from the ones that we haven't (bulbs grown from seed are almost always free of virus). As emotional and painful as it may be to destroy a virused plant, it is much better do this than to have it spread to other plants in our collection. It is my understanding that many beautiful and sought after geophyte species in cultivation exist as single clones. This is a serious concern if a species is self-incompatible, refuses to produce seed and all clones in cultivation become virused. It can be tempting to tell ourselves that we can perpetually isolate a virused plant because we can't bare to destroy it and that we can keep it from infecting other plants forever. But an infestation of aphids, for example, could occur while one is on vacation, ill, or too busy with work or family to spray the plants and in that time virus can be transmitted to dozens of plants from one infected plant. Why risk it? Remnant roots in potting media and the ground in which virused plants once grew can serve as reservoirs for virus to re-infect susceptible plants if they are planted in the same soil. Virused plant material and its potting media should not be composted because most compost piles/bins do not get hot enough to kill viruses evenly. Terracotta pots are very difficult (if not impossible?) to sterilise and should not be re-used. Plastic pots can be reused after being soaked in a bleach solution, scrubbed and rinsed. Cutting and cultivating utensils must be sterilised between each clone. Smokers should wash their hands thoroughly before handling plants (see Tobacco Mosaic Virus). Pests can spread virus: aphids, thrips, mealybugs, and scale. Snails, slugs and some birds that eat flowers can also spread virus mechanically. Finally, when pollinating between a virused plant and a healthy plant, it may be better to use the virused plant as the receptor of the pollen (mother of the seed), as sometimes pollen from a virused plant may infect the healthy plant if applied sexually. As bulb lovers, we all come to this hobby via different motivations and we get different things out of it. Our collections also change over time just as we do as individuals. So why care about viruses that may discolour our plants' leaves and flowers but haven't killed them or noticeably slowed their growth? Virused Rembrandt Tulips (of old) were so gorgeous that they once famously caused the Dutch economy to go boom and then bust - proof if there ever was of the charisma of that even heavily infected plants can have on us. Or why should we be educate ourselves about viruses than can cross over from asymptomatic non-geophyte ornamental plants in the vicinity of our bulb collections? For some it may not seem to matter much or it may not seem like what we do in our own gardens couldn't really make a big difference. However, I believe that how we manage the health of our collections does matter and that aside the most important result of our bulb hobbies is what legacy we will leave others from it. Jacob U. Knecht ---------- - http://www.flickr.com/photos/morabeza79/