the systemic movement of the virus was hindered. The virus moves through the xylem to infect plants systemically, but can also spread locally through cell-to-cell movement. In host plants, the infected tissues include both leaves and the cytoplasm. It has been shown that PMTV infected seeds are planted, they only partially infect the following generations of plants, showing that its vector, S. subterranea is very important for transmission. Environment The vector for PMTV, S. subterranea, is a slime mold known to cause powdery scab disease that favors wet and humid conditions, specifically poorly drained soil. In fact, this disease doesn’t occur often in areas with less than 30 inches of rain per year. The chance of disease onset increases in areas that get more than 45 inches of rain per year. Such moist environments helps facilitate the vector's zoospore movement to the infection sites (roots and tubers). It is thought that powdery scab disease development increases when high soil moisture gradually dries out, as this increases zoospore germination. S. subterranea tends to prefer more acidic soil, ranging from pHs of 4.7 to 7.6. S. subterranea thrives in temperate conditions, between 52 and 75 degrees Fahrenheit, with the optimal temperature for infection by the vector being 60 degrees. Disease development can also be encouraged by certain agricultural practices. For example, increased use of nitrate or ammonium nitrogen containing fertilizers increases the incidence and severity of powdery scab disease, caused by the PMTV vector S. subterranea . This can be due to the fact that fertilization enhances root growth, which provides a larger amount of tissue that can be infected. Management Chemical treatments for field application against viruses are currently not available. This holds especially true for potatoes, because once infected by a virus, they will stay infected for the remainder of their lives. Thus, preventative methods are more viable options. This includes methods such as resistance-breeding, vector management, and crop sanitation. Resistance-breeding, or generating plants that are genetically resistant to pathogen infections, is another option being explored. Generating vector-resistant plants have been proven to be largely unsuccessful for PMTV. This is because plants need to have immunity towards S. subterranea in its tubers, roots, and stolons in order to completely resist infection by the vector and virus. To this date, however, potatoes have been produced with resistant tubers but susceptible roots. Although resistance breeding has not yet provided benefits for commercially