Question
We bought our house outside Atlanta, GA 16 years ago and have always had a beautiful St. Augustine lawn.  About 5 years ago it seemed our lawn was disappearing and found out thru our local county extension office that we had chinch bugs.  Luckily we were able to keep the rest of the yard under control.  However, the last several years that patch of ground never recovered even after re-sodding twice.

Now, after a severe drought last year, no matter how hard I tried prevention, the chinch bugs ate 75% of our yard.  I have read many articles saying our lawn will not recover and will need to be resodded.  We had a soil test done that basically said our PH level was a bit low at 5.2.  

My questions are, do you think our lawn will recover this year and is there anything that can be done to help it at this point?  With a very mild winter this year, the yard is full of weeds so fertilizing is not recommended.  Also, do you think lime will help at all? Do chinch bugs actually infect the soil?  Thank you so much.  We are trying to avoid paying thousands of dollars to resod this year.

Answer
Resolving a lawn problem is a matter of eliminating causes; and the first one we are going to eliminate is insects. Pour 2 oz. dish washing liquid in 2  gallons water and pour this gently over 2 square feet of the lawn. (2 x 2 x 2).  Select an area where there is some grass. You want the solution to go down into the soil; not across the surface.
In a short time you will see every little animal coming up to the surface. Most of them will be harmless so you will need to identify the harmful ones. Learn to recognize the differences between the two groups. The young stages of chinch bugs are red with a white band across its back. Caterpillars are generally harmful.
At the end of the exercise you will know whether or not you have an insect problem.
If you feel like you are on a roll, look for grubs. You will need something like a post hole digger to go down a little deeper - 18" or so. If grubs are present, you will need to find out what kind they are and when they will come up to the surface to feed. (Some have a 3 year life cycle). You can waste a lot of money and time by applying treatment at the wrong time.
If insects are eliminated then harmful nematodes might be the cause. These are identified through a soil analysis (there is a cost) through the Extension Services. They will advise you how to treat.
A pH of 5.5 is within the range for growing a good lawn; liming is not necessary.
Now for your other questions:
No; I do not think that your lawn will recover on its own. The strategy is to preserve whatever little grass remains; get rid of the weeds and insects (if they are real problem)and promote growth by fertilizing and watering.
If the damage has been massive, re-sodding  may well be your most economical option.