ako0396,
Can you post a photo of your entire garden? What type of soil mix or planting medium are you using? Did someone water the plants while you were away for the three days?
I agree with chelle that it could be a chemical burn from the fertilizer. Miracle Grow is supposed to be a 'foliar' type fertilizer but I find that the sun can quickly harm the plant if the solution is not rinsed from the leaves.
I agree that you should not have to spray for every insect the minute you see it. Either pick off the bugs if possible or use a spray of water from the hose to knock them down as Weedwhacker suggested.
Maybe using a lightweight fabric floating row cover would help to keep the insects off the plants. Since you are working with a raising bed that could be an option.
