An alternative option is to take a method from fig growers, who bundle up their trees to protect them from cold. The difference is that you can bundle up peaches to protect them from rain. I live in W. Washington and peach leaf curl is rampant. It takes using small pruned, or genetic dwarf, peach trees like Ponderosa (Or is it Bonanza?) or Honey Babe or Garden Gold (My varieties). I bundle up the branches with twine, each major branch being one bundle. Then I cover each bundle with a white plastic trash bag "sheath" and tie that in place as well. Keeping the rain off the buds, prevents peach leaf curl spores from getting into the buds and growing. I've sprayed the bundles before covering with copper spray but not sure if it's necessary. The bundling needs to be done in November. Then in February, I remove the trash bags and unbundle. I watch for when buds begin to swell, then remove the bags. This technique changed my peach loss from almost 100% to an overabundance of peaches. Only a few leaves were infected wtih leaf curl. I also did this with a Tri-lite peachplum, which is not genetic dwarf but is small. It worked for that as well. I plan to keep it pruned small so that the bundling is reasonably easy.

how do you know the spray didnt get rid of the bug you never saw ... i am sure.. nowhere on the label did the spray claim that it would heal the leaves ... without a pic.. there is no way to help you.... nor without an ID of the problem ... ash are dying all over the US from EAB .... where are you ... i would not invest too much emotionally in an ash ... good luck ken

Ash trees are prone to have Wooly Ash Aphids this time of year which sip the fluid from the cells of new leaves leaving them curled or crinkly. In the process they excrete 'honeydew' which is a sticky, shiny, sugary substance which can fall on leaves, sidewalks and lawn furniture. A strong blast from the hose can dislodge them if the tree isn't too big. Here is a link that might be useful: Wooly ash aphid

That looks like slime flux, which is a bacterial disease of the wood. It causes the sap to ferment inside the tree, raising the sap pressure, and making it bubble out any weak places in the bark, such as branch crotches or wounds. It is commonly spread by dirty pruning tools, so be sure to wash your pruning tools in 10% chlorine bleach solution after pruning this tree, to keep from infecting other trees. Normally the home gardener can't do anything about it, though a well fed and watered tree sometimes will shake it off, after a few years. A better bet is to contact a certified arborist--he may be able to inject antibiotics into the tree and stop the infection. Good luck! : /