Answer: Crabapples are susceptible to a fungal disease called scab. This disease causes spots on leaves, and can affect the fruit, making it deformed and spotty. Once scab attacks a tree it's difficult to control. Although you've been spraying to control the problem, perhaps your timing is just a bit off. The best thing for you to do is to rake up and distroy the fallen leaves and remove the fruit at the end of the season. Then in January or February, spray your crabapple tree with a fungicide (such as lime-sulfur) to prevent the disease from reappearing next year. Lime-sulfur is also marketed as dormant fruit tree spray or Bordeaux. It's used on apple trees as a precautionary measure because apples are quite susceptible to scab, too. Reapply according to label directions (up to 4 times in the spring). Hope this helps. Best wishes with your crabapple!
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