Huston I'm no disease expert but usually this early in the season Daconil applied weekly will help a great deal in stopping initial infections of many foliage diseases but it doesn't stop them all. I don't see any gray mold on those leaves which is the disease I use the bleach spray for the most often. It does look like you may have early blight and possibly something else so you might want to remove the foliage that is showing damage immediately.
I spray Daconil every week from the time my plants go outside to harden off until I start seeing some definite disease symptoms. At this point I will use the diluted bleach spray and then alternate using a copper spray then Daconil spray. If I see any gray mold or late blight symptoms then I use the bleach spray as soon as possible then follow up with a copper spray the next day. Two days after using the bleach spray it will be obvious what foliage needs removing because the diseased foliage will shrivel up and die.
I do use the bleach spray at a slightly milder solution as a preventative on squash, cucumbers and melons because it works wonders at preventing or stopping the mildew diseases that those crops are prone to get sometimes. A good friend of mine uses the bleach spray as a preventative spray and doesn't use any other fungicides and he doesn't seem to have any more problems with foliage diseases than I do. I do use the bleach spray during periods of continuous thunderstorms and rain. I just go out between showers and spray with the bleach spray. It seems to make a big difference in the amount of disease that shows up on the plants after the rains stop. The reason I do this is because the preventive fungicides get washed off and the bleach spray will kill most bacteria and fungus that is starting to develop during the rainy times so that they don't get a good foothold on most of my plants.
Another thing you can do that will help is to keep all the lower foliage removed so there is at least a foot from the ground to the first leaves. This helps prevent splash back when watering or during rainfall. It also helps to have a good heavy mulch under the plants. Pruning the plants to prevent foliage from becoming too dense is also helpful in our humid conditions.
Down here it is important to keep a preventive fungicide on the plants so weekly spraying is necessary. I have had the best luck starting my season out with weekly spraying of Daconil. Later I will alternate a copper spray with Daconil. The bleach spray is used mainly once I see some disease symptoms that neither the Daconil or copper have prevented. You will have to experiment some and see what works for you and be ready to adapt to changing conditions. When frequent showers are a problem the copper spray may be better at times because it doesn't seem to wash off as easily; but if heavy rains are persistent then the bleach spray becomes the best alternative to use between those frequent rains.
Bill
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