Not sure what this is, but I've seen it on some of my plants recently here in PA. Wasn't there last week, but we've had non-stop rain and a few colder nights since then. If anyone can ID this, it would help me as well.

btw...if you right click on the image and save/copy the image url and paste it in your browser you can see these a little bigger.

@randy41 I don't want to step into an apparently professional relationship between you and your extension agent, particularly since you appear to be growing on a commercial scale while all I have at stake this year is a few garden plants. However, there are a couple of things to ponder. I looked up the label for the Nordox products and find that they contain up to 75% copper oxide granules. They rely on a slow release of copper ions to kill the organism. That would certainly be effective but I rather doubt that NadineNJ, Battalina or, for that matter myself, would be able to obtain very much of this stuff. They are also going to rely on the product remaining in place for a long period of time and the Nordox company claims that it does, "Famous worldwide for high retention". Nonetheless, I would expect that you are going to have to re-apply, perhaps frequently and that the product is pretty expensive. I would also tend to wonder what effect there would be on new growth, i.e. foliage developing after your Nordox application. Another point made elsewhere is the possibility of soil contamination with the copper. It is claimed that the copper will bind with some components of the soil and render you with a toxic field. I did find, some time ago, albeit on a casual basis, an assessment of such a condition in Italian vineyards where they had used Bordeaux mixture for generations. Apparently there was less copper than anyone had expected but still a significant amount. Still, 75% is a whole bunch of copper and, in your shoes, I believe I would wonder about that. Soap-Shield is specified as 1.8% metallic copper equivalent. Epsom salts? Seems to me as if somebody is flailing a bit here. Look around and you will find people recommending all sorts of things including manure tea and even sour milk. I don't wish to demean anyone, especially as there are lots of highly dedicated people trying very hard to help others and often providing yeoman service under highly demanding conditions. All the same, I think that if I were considering an application of Epsom Salts or anything else, I might like to know a little more about the expected MOA (mode of action) for the product. I am a bit leery of the statement that "late blight does not spread when temperatures are above 86 and the foliage is dry". I have learned over the years to take such "accurate" claims with a grain of salt. Where does anyone get such a specific temperature point to rely on. Is that field experience or did someone do a lab run in petri dishes with a carefully controlled and constant temperature? Which temperature is that? The high of the day? The low? The mean or average? I have seen the point made very recently (maybe on one of the Cornell pages, but I can't remember) that the Late Blight organism produces and releases most of its spores at night. My overnight temperatures and, I suspect, yours are a lot lower than 86. Also, when I inspect my plants, usually each morning, I always find the leaves quite wet from condensation. I too am "waiting for the blight to take off again" and know full well that there will be periods of increased spore development and weather conditions conducive to infection. On the other hand, it is now more than six weeks since my initial application of the copper soap mixture and in that time there have been periods of cooler weather and repeated rainfall, though no long periods of drizzle and humidity. I agree that we all watch and wait with little assurance of the future and that there will be successes and failures to follow. I have put forward my suggestion, possibly too early, in the full knowledge that it requires lots of additional confirmation or falsification. Nonetheless, I wrote it here because I've seen questions posted by people who are rather desperate and I have something that is working for me, at least for now. Good luck.

It looks like early blight to me, here is the link http://plantdiagnostics.umd.edu/_media/client/diagnostics/gallery/early_blight_with_fruit_l.jpg You will know, if it is late blight tomorrow, it is extremely fast happening: I came from 2 days trip and my gorgeous healthy stout tomato plant was absolutely destroyed by late blight. You will know the moment you see it. I now check every morning all the tomatoes leaves, some with charachteristic spots, I am using a sparying program in one of my gardens. The best site for late blight pictures is Cornell's http://images.google.com/imgres?imgurl=http://www.hort.cornell.edu/department/Facilities/lihrec/vegpath/photos/images/late_blight_tomato_stem2x1200.jpg&imgrefurl=http://www.hort.cornell.edu/department/Facilities/lihrec/vegpath/photos/lateblight_tomato.htm&usg=__QBs-_ijN6R_JKR5WbxR21EO1Axg=&h=841&w=1200&sz=195&hl=en&start=17&um=1&tbnid=3ENxH_UNnkDHEM:&tbnh=105&tbnw=150&prev=/images%3Fq%3Dtomato%2Bearly%2Bblight%2Bcornell%26hl%3Den%26rlz%3D1T4SUNA_enUS238US290%26sa%3DN%26um%3D1 Hope, this helps, Good luck