Does copper fungicide cure blight on spruce and other evergreen trees? If trees are currently infected how often should you apply applications? I live in Oklahoma City.
Once the canker has formed the copper does no good. It will prevent the spores from entering the foliage BUT with most fungicides you will need to spray as the new growth is budding out and at 10 day intervals until no new foliage is budding (mid July0. If the weather is wet then tis will increase the amount of problems with blight. IF the blight is only on the foliage I would teat every 10 days to prevent the spread to new foliage. The fungicide will not help the infected foliage and you can expect it to turn brown and fall off.