In Pennsylvania last summer, we had a big problem with blight on tomatoes and peppers. To combat fungus problems this year, try this organic spray early in the season. I found this tip courtesy of Rodale and it’s very effective in fighting black spot and powdery mildew. All of the basic ingredients can be found in your kitchen. 
Mix 1.5 tablespoons of baking soda; 1 tablespoon of insecticidal soap; and 1 tablespoon of canola oil with 1 cup of water. Then add 1 tablespoon of vinegar (it’s important to add the vinegar last so the liquid doesn’t bubble over). Pour the mixture into a backpack or pump sprayer, followed by 1 gallon of water. Shake well to mix.
Attention: Make sure your backpack or pump sprayer hasn’t been used for spraying an herbicide or you may harm your plants. Wash your sprayer THOROUGHLY before adding the mixture.
Spray tops and bottoms of leaves and the stems. The canola oil makes the substance stick to the plants and the insecticidal soap helps fight insect pests.
P.S.: Don’t overuse this treatment – use only occasionally. Repeated applications of oil can harm your plants.
I'll do my best to answer it.
That is a great old recipe –
I’ve also added a bit of Maxicrop to the spray to enhance its productivity -