According to plant pathologists, this killer round of blight began with a widespread infiltration of the disease in tomato starter plants. Large retailers like Home Depot, Kmart, Lowe’s and Wal-Mart bought starter plants from industrial breeding operations in the South and distributed them throughout the Northeast. (Fungal spores, which can travel up to 40 miles, may also have been dispersed in transit.) Once those infected starter plants arrived at the stores, they were purchased and planted, transferring their pathogens like tiny Trojan horses into backyard and community gardens. Perhaps this is why the Northeast was hit so viciously: instead of being spread through large farms, the blight sneaked through lots of little gardens, enabling it to escape the attention of the people who track plant diseases.
In my summary, this article makes another case for Buy Fresh-Buy Local in the case of starter plants. I'm not sure if the information is fact or theory, but it makes some sense. It will make me think more about my source choices