Answer: It's a fact of nature that in order to grow tree fruits, you need to commit to the time and energy required to protect them. To avoid scab problems, your apple trees can be sprayed with Bordeaux (lime-sulfur). This fungicide must be applied early and thoroughly to protect new growth. Apply according to label directions; as the buds break until the leaves are fully expanded. Do this at prepink, pink, calyx, and first cover. Since the fungus overwinters in fallen leaves and fruit, be sure to thoroughly clean up and dispose of plant debris in the fall months.
The horticultural oil you sprayed is effective against overwintering scale insects and insect eggs so you shouldn't have many problems with them this year.
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