Not sure if the poster you addressed will reply, given his post is a year old. His images appear to be symptomatic of the physiological disorder, oedema - see below. Given your issue is in the upper (youngest) leaves, it might not be the same. It's not unusual for leaves of F. lyrata to emerge with pinhead or slightly smaller size dots covering the leaf surface nearly entirely. This often occurs when the air is dry, as it usually is in winter or when air conditioning is operating for days on end. That particular condition is simply expression of the purple pigment anthocyanin, and it will fade as the leaves mature. That's said w/o my being able to see an image of what you're describing, which would be very helpful. Oedema Oedema is a physiological disorder that can affect all plants. It occurs when the plant takes up more water than it can rid itself of via the process of transpiration. The word itself means 'swelling', which is usually the first symptom, and comes in the form of pale blisters or water-filled bumps on foliage. Under a variety of circumstances/cultural conditions, a plant's internal water pressure (turgidity) can become so high that some leaf cells rupture and leak their contents into inter-cellular spaces in leaf tissue, creating wet or weepy areas. Symptoms vary by plant, but as the malady progresses, areas of the leaf turn yellow, brown, brown with reddish overtones or even black, with older damage appearing as corky/ scaly/ ridged patches, or wart/gall-like bumpy growth. Symptoms are seen more frequently in plants that are fleshy, are usually more pronounced on the underside of leaves, and older/lower leaves are more likely to be affected than younger/upper leaves. Oedema is most common in houseplants during the winter/early spring months, is driven primarily by excessive water retention in the soil, and can be intensified via several additional cultural influences. Cool temperatures, high humidity levels, low light conditions, or partial defoliation can individually or collectively act to intensify the problem, as can anything else that slows transpiration. Nutritional deficiencies of Ca and Mg are also known contributors to the malady. Some things that can help you prevent oedema: * Increase light levels and temperature * Monitor water needs carefully – avoid over-watering. I'd heartily recommend a soil with drainage so sharp (fast) that when you to water to beyond the saturation point you needn't worry about prolonged periods of soil saturation wrecking root health/function. Your soil choice should be a key that unlocks the solutions to many potential problems. * Avoid misting or getting water on foliage. It slows transpiration and increases turgidity. * Water as soon as you get up in the AM. When stomata close in preparation for the dark cycle, turgidity builds. If you water early in the day, it gives the plant an opportunity to remove (for its own needs) some of the excess water in the soil. * Put a fan in the room or otherwise increase air flow/circulation. Avoid over-crowding your plants. Questions? Al

2nd picture

Appears to be the fungus entomosporium, not anthracnose. The latter is a 'catch-all' term used by those who know just enough to get themselves into trouble. Mountain Ash happen to be quite susceptible to this disease. The fact that they have been through some serious stress compounds their inability with withstand disease and insect attack. One spray will never 'cure' them. These fungal spores are ubiquitous....and your plant is prone to infection. That makes control a challenge, especially once the disease has expressed itself. When the leaves fall this autumn, be sure to rake up and remove them from the area. Put them to the curb for pickup, don't use them for mulch or compost. Avoid excess fertilization or pruning practices that may stimulate lots of new growth. There are fungicides on the market that can help you control the disease and they are readily available. I never make chemical recommendations in the GardenWeb, but I know that with a little bit of research you can come up with what you need to know. Peeling bark would certainly worry me. Perhaps you could link some images of the trunk, fairly close up as well as from enough distance to see normal bark tissue, as well. The fact that the flowers appear to be perfectly healthy is of little or no significance. In the future....FYI.....smaller plants establish much more easily than larger ones.

Willows are prone to all manner of fungal issues on leaves and most fungal problems are exacerbated by wet, warm springs. It is seldom necessary - or even practical - to treat for these, as most are more unsightly than actually damaging. Unless defoliation is severe or the problem returns year after year. Good sanitation, including raking up and disposing of all infected foliage, will help a lot. And insect problems are often a secondary effect of a tree under stress for some other reason, including diseases. Again, not at all necessary to treat at this time of year, when leaves will be dropping soon anyway. If the tree is of a manageable size, a dormant season spray (dormant oil) could help to smother any overwintering spores or insect eggs.