HOW IMPORTANT IS VECTOR CONTROL?
This is a hard question to answer because the benefit of vector control depends on many factors including 1) the sources of virus inocula, 2) the size and activity of the vector population and 3) the type of virus. Most airborne vectors of virus entering a dahlia planting will not be carrying dahlia viruses. Therefore the most likely and important source of virus is your dahlia collection. Did you plant infected dahlias? If so there will be a greater need for vector control. The level of vector activity (numbers, types, amount of migration) varies from year to year. Temperature, rain, predator populations, length and severity of winter, daylight length, types and quantity of vegatation in the area and many other factors influence vector activity. Some years vector populations will be so large and active that protection of dahlias from virus will fail. For example, in the Palouse region of Eastern Washington 1 year out of about 7 the aphid population is so active in the spring that fiel
