Late blight is caused by Phytophthora infestans. It's a fungus, and unless you're spraying stuff for it, there's not much you can do about it if it shows up in your area. Its spores can be spread by wind, contact with workers, or even over long distances by windy weather patterns. Hell, they can even swim if it's wet enough. Most farmers do spray for late blight, but they may not be spraying for it this early in the season. Hence the name "Late Blight." Phytophthora is a bitch to get rid of once you've got it. You can fumigate, and spray a ton of chemicals and you may still see some in your crop.
Wordwiz, I'm glad you've not seen any blight of any kind. Blight is just a generic term in most cases for a defoliating disease, and in tomatoes there are early blight, late blight, southern blight add infinitum! Proper crop rotation is key to preventing any plant disease, so keep this in mind for next year. Of course, I'm sure you already know all about that as it sounds like you've had plenty of farming in your background! Another Phytophthora you might have experienced in your Tobacco farming past is Black Shank. It can do a number on tobacco, and causes that stunted growth, darkened stems and withered leaves, and a "disking" in the stem where it looks like a stack of poker chips in the stalk.d
