Q.My Holly Bush Is Being Covered With A Black Fungus
This is my 5th year here and last year my Holly bushes had a lot of big flies and this year covered in what looks like black dirt. I sprayed twice a week apart with name oil. Cannot find a description of what is wrong. This is some type of fungus.
Certified GKH Gardening Expert
It looks like sooty mold, which grows in the honeydew produced by scale and aphids. You should be able to wash it off but look for the insect that is causing it. The neem oil should have helped eliminate the pest, however, if it's scale they are more challenging than aphids to remove.