The internet is abuzz with stories of a developing pandemic of Late Blight (Phytophthora infestans), which is disastrously fatal to tomatoes, potatoes and eggplants. This is the disease that caused the Irish potato famine, and is not to be messed with.
A recent AP story on Yahoo quotes Meg McGrath, professor of plant pathology at Cornell University, as saying that Late Blight is "worse than the Bubonic Plague for plants."
Outbreaks have been identified in most of the eastern states, including West Virginia and Virginia, where most of the plants in our garden came from. I haven't seen many signs of infection anywhere in our garden except perhaps on the first fruits of the Early Girl tomato plants we bought over at the Southern States store, which sources most of its seedlings from the same supplier (Bonnies Plants) that the big box stores do. The plants themselves (as well as the rest of the tomatoes) look very healthy, and are starting to set fruit like crazy. Fortunately for us -- unlike more northeastern states -- we have not had a lot of rain, which is the main way the blight spreads. Also, I have done one spraying of a compost tea which includes Bacillus subtilis, and beneficial competitor to the Late Blight fungus, and that may be helping as well
Nonetheless, we will be on the lookout for symptoms, and so should you, especially if you live in an area that has seen a lot of rain recently. Cornell has an excellent web primer on Late Blight, including photo identifications. Ohio State also has a nice fact sheet that will help you determine if your tomatoes, potatoes or eggplants are infected (peppers are less bothered). One key element to understand is that Phytophthora infestans cannot survive without live tissue to colonize, and so if you do identify symptoms you really should yank up the plants to prevent its spread. No spray, organic or synthetic, is going to stop it once symptoms are present. So just do it!
