I have different types of basil and all of them have gotten this infection that leads to massive leaves death.
This problem starts being a little black spot that expands in one day to look like a gray star with a black spot in the center. The gray star becomes in a same shape blister. I have separated this blister from the leaf and I could see the black spot stuck to the leaf and all the surface inside this blister looks shiny and moist.
Please take a look in detail following this link: http://farm3.static.flickr.com/2245/2431563808_0e5a380bfa_b.jpg
I will appreciate if some of you could please give me some advice to restore my plants to health.
Thanks a lot, I hope I don't have to burn them all.
I have this EXACT same thing happening to my Basil and this is the only image online I can find that matches it. Did you ever find out what it is? I'm trying to cure my basil pant, but it doesn't look like any of the known fungus' that attack Basils (from what I read and see online)
I have the same in my basil, and it did spread to mint. I wonder if it is the leaf spot named "cercospora". I am having trouble with another kind of cercospora atacking a Surinam Cherry tree. I have been eliminating the sick leaves of all plants everyday, and it seems to keep the disease at control, until I find a way to cure the plants. I heard that cupper based stuff can cure it, if you are willing to use chemicals.
I have the exact same issue. If you look very closely at one of the bigger spots, you'll notice that there is actually a very small worm inside the spot between the top and bottom leaf surfaces (inside the leaf). I actually had to pull the leaf apart before I was able to find the culprit inside. This pest is attacking all my basil plants. I haven't seen it on anything else. I haven't been able to figure out what pest this is, but it is not a disease.
I was dealing with the same thing! I ripped the lead apart and sure enough there was a worm. The black spot is a best as I saw little babies running out! The question is...what do I do to salvage the plant now that I know what it is.