What is your virus protocol?
A: This is a tricky topic. We do not claim to be scientists or plant virologists and much more extensive research needs to be done in the field of dahlia viruses. First and foremost, we sanitize our tools (with a virucide / bactericide / fungicide / mildewstat) between every single plant when harvesting stems, dividing and taking cuttings. We do not host U-pick events in order to prevent contamination of our stock. With cuttings, the cuttings from one tuber go into their own separate mini-pod that isn't shared with any other cuttings from any other tubers. In our indoor grow room, we only water the plants from the top so that they don't ever share water between plants.
With that said, virus is part of nature. It's not going away. If one virus is eradicated, a new virus will emerge. We don't take any chances with spreading virus within our stock, but it is impossible to prevent entirely since there are so many vectors. Microscopic insects are the most common vector, such as thrips and aphids. We have an aggressive insect control regimen and use an electrostatic sprayer that covers all sides of the leaves. We rotate insecticides to avoid resistance and typically spray every 14-21 days for maintenance and prevention. Just to add, our dahlia area is a significant distance from our home, our pets and any neighbors. Please don't judge, we're just trying to keep our plants healthy. We will be looking into using beneficial insects to control the bad bugs in the future, but need to do more research first. A plant that is virus-free one day could be infected the following day by a single bug. Recent studies have concluded that 85-90% of dahlias carry some form of virus, but don't panic! Not all viruses are the equivalent of Ebola. If you were to test your grass, trees, and landscape plants, you'll find virus there too. Personally, we feel that Mother Nature isn't given enough credit to overcome obstacles on her own. Every living thing has an immune system, albeit very different mechanisms. TLC, in different forms, can help fight off virus (although our bodies or plants may still contain evidence of prior infection). If we have a plant that is not performing well, we give it TLC and micronutrients, and an extra spray of insecticide (to prevent spread by insects in case it is sick), and time. If it rebounds beautifully into a productive plant, we thank Mother Nature for "doin' her thing" and move on. If a plant doesn't rebound, we pull it, place it in a plastic bag and put it in the trash (not compost). The one exception to that is TSWV - Tomato Spotted Wilt Virus. It can affect thousands of different plants and can be particularly harsh on dahlias. Fortunately, we haven't seen many instances of TSWV on our farm. However, if we see the telltale bullseye ringspots, we pull that plant immediately. We might be overreacting here, but until we know more, we won't take any chances with TSWV.
We cannot guarantee virus-free stock (and if anyone can, it likely won't stay virus-free for long unless it's grown in a vacuum). We pull any plants that don't perform well after being given TLC and nutrients. Plant performance is one of our top priorities. But given the statistics, virus is a risk we all take when purchasing dahlias. It is nearly impossible to trace when and where a plant was infected and we cannot take responsibility for those unknowns.