Note: Shake well before and during application. Water the plant well the day before you spray. Do not spray during the heat of the day in full sun. Reduce potential injury by rinsing the plant with fresh water a few hours after the soap spray application. Thorough coverage of the pest is necessary so spray both sides of the foliage thoroughly until it drips form the leaves.
Spray every 5-7 days as needed.

If a fungus is also present then add to the above formula: 2 Tbsp baking soda

Note: Shake well before and during application. If the weather is humid or the threat of disease is high, spray every five to seven days. Spray both sides of the leaves thoroughly. Always test any spray on a small area of the plant. Can be used against blackspot and mildew on roses, powdery mildew on summer squash, early blight on tomatoes and alternaria leaf blight on melons, and who knows what else !

The use of soap or oil for insect control will control the insects but will do nothing to correct the condition that is making the plant susceptible to the insects. Using foliar applications of fish emulsion and seaweed may help ill plants do better.

Another control for the fungus Powdery Mildew
Spray a milk solution (a minimum of a 10% concentration which is 1 cup of milk in 9 cups of water) sprayed twice a week. The milk was shown to be as effective or better than conventional fungicides.
(Research conducted in Brazil and published in the journal Crop Protection vol. 18, 1999, pp 489-92)

Use aspirin to fight fungus too ! Dissolve ¾ of an aspirin in a gallon water and spray every two to three weeks. The aspirin will boost the plants defense mechanism. (Testing done at the University of Rhode Island showed that tomato and other plants tested also yielded more fruit than those treated with commercial fertilizers,.)

Can it be applied as a preventative every 5-7 days as well? If it works that well, then I will use it as a maintenance if possible.

yes, I try to find natural remedies first. To date, I have not had to use any harsh chemicals (unless Copper Fungicide is considered harsh) on my garden.

Only thing I use is Bt, Neem Oil and this handy recipe above. If this recipe can do what Bt and Neem does..then I will use it exclusively!