Question: My aucuba plant has black leaves. Is that a disease? Is this fire blight?

Answer: No. That’s almost always some form of sun scorch. Aucubas can’t take any amount of direct sunlight. If you look closely, you’ll probably see that the leaves that poke out into more light are most blackened. Fire blight attacks only plants of the big rose family. Aucubas are not in that family.