Question

How do I get rid of some fungus type looking stuff on branches of my Italian plum tree

Answer 1

Two ways, first:

You can burn cedar branches and direct the smoke to your infested tree, or,

Second:

You can spray the tree with a mixture of vinegar 20%, vegetable oil 20% and water 60% with a teaspoon of sea salt, (one teaspoon of sea saly per gallon of water),  If you choose to spray [which is the easiest method] than spray in the morning before the sun is full in the sky,  You should only spray your tree three times max. and wait a day between the sprays. You should see the results in about 2 weeks,  -Birdy

Answer 2

after the sun goes down mix up 2 1/2 tablespoons 3 % hydrogen peroxide medical grade with 1 gallon of water.  use protective gear, long old clothes, mask, goggles and hat.  Keep children & pets away.  This could be black knot a fungus. Spray real good when it is not windy.  Use the whole liquid.....do not save this.   If this is black knot it is very hard to control.  We had to take down 22 trees because I did not have this recipe then.  We even trimmed the effected areas wiping the blade with alcohol after the cuts.........The forrester said that we had wild plum trees in the woods and they have it.  But we live between 4 high mountains and that impossible for us to climb them and cut them down.  We burned the wood in an antique coal fired furnace that we were fortunate to acquired for the barn for the winter.  Kept it comfortable when we worked inside.