That is a nice list of resources Stu provided for you. If you think of how a tree utilizes sunlight, you can infer that damaged leaf surfaces will slow photosynthesis and therefore overall growth of the tree. So, for CAR and scab as well, growth will be slowed in trees with foliar damage. How much is something I've never seen investigated (nor have I looked). When I put in the bulk of my trees, I went with DR varieties, and didn't spray at all for the first 3 years. I didn't lose a tree and things seemed to grow fine. We started a minimal spray program this past year on some eaters in the yard. My guess is that some of my less DR trees would be a bit larger had I sprayed from day 1. If you step back, however, and look at the big picture, you are a deer manager. I just can't justify the time/expense/environmental impact of spraying deer apples as we have a large number of DR cultivars at our disposal. As mentioned many times on these forums, if you plant Freedom, Liberty, Enterprise and Goldrush, you have drop times more or less covered. I personally believe you could never spray these and get plenty of apples. I would add Yates to that list as it has produced yearly for me without spray, and Violi's crab as well. I agree with Stu that scab is a far more important pathogen than CAR in a no-spray situation as well. One thing to consider and something that many of us are doing is find some local wild trees that seem to look clean and bear every year without spray. If you can find a few of those with varying drop times, you have hit the jackpot. Graft them to your rootstock of choice and you will be set in a few years.