Because it's been cool and wet in the northeast the leaves have not hardened off much so Captan will burn the young foliage. It shouldn't cause significant damage and is generally considered only a cosmetic problem. The commercial growers use it anyway.

Myclobutanyl will control scab without burn,lasts twice along and doesn't wash off. Captan is often added with it to delay resistance but for a couple trees you could safely go without it.

Great info Harvestman!

Thanks Mudflapper. I forgot to mention that one advantage and disadvantage of using Captan is that it's habit of washing off in rain also allows a certain amount of redistribution to growing tips. A systemic like myclobutanyl doesn't protect growth that comes after spray but to a certain degree, Captan is said to. However, on trees that I've sprayed with Myc. only I haven't paid for this difference in any recognizable way so I'm not sure if this is a real field tested problem or just a researchers hypothesis.