It appears you went offline without seeing the photos I posted. Because I don't want you to have to wait any longer, I'm going to go ahead and answer without your input. Though it's impossible to be certain based only on an online description, from what you have said, it sounds like your trees are infected with cedar apple rust. This is a fungal disease with a very complicated life cycle. Orange clusters appear on cedars and junipers when new spores are ready to be released. Those spores then are blown through the air to infect, apples, pears, quinces, and other trees in that family. Mild cases may result in only a few yellow spots. severe cases develop the way you have described. If you had a wet spring, that can increase the severity. Cedar apple rust doesn't kill trees, but it does disfigure them. The trees may even lose all their leaves, but new ones will grow next spring. Once the rust appears, it will usually be back every year.
Pesticides registered for use include captan
, mancozeb, maneb, sulfur
, thiophanate methyl (Cleary 3336), thiram, triadimefon, and ziram. If you diluted your captan more than the instructions stated, it may have been too weak. However, it is just as likely that you sprayed too late. Once the yellow spots appear, it will do no good to spray. The fungicides are used as a preventative in the spring before the disease can take hold.There will be nothing you can do this year.
To prevent an infection next year, start with dormant oil to be applied in late winter to destroy overwintering spores on bark, branches, twigs, and buds.Follow that in the spring with a fungicide according to package directions,first when the flower buds turn pink, again when the petals have fallen, and once more about 10 days later. In the fall, remove all the apple leaves - don't compost them. You'll have to repeat this procedure each year.
If you have more questions, let me know in a REPLY. I wish you success in preventing the disease next spring.
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