I work for the State of California. We have six coral trees, the exact species I have no idea. Something in infecting these trees. It appears to be a dark fungus attacking the bark. The bark peels back and falls away leaving truck and large limbs bare. The infected trees show few leaves and otherwise do not appear healthy. What is this and what is the remedy? Can they be saved. The trees are nearly twenty years old. They are on the north side of an office building.
I have an idea that California is a fairly climatically diverse place. Are you in San Diego or Susanville? According to USDA Agriculture Handbook 165 (Index of Plant Diseases in the United States. USGPO. Washington, 1960), the following diseases are reported from species of Erythrina (coral tree): Cercospora erythrinae (on leaves), Cercospora erythrinicola, Clitocybe tabescens (root rot), Colletotrichum erythrinae (on leaves), Dicheirinia binata (rust), Meliola bicornis, Meliola crenatissima, Meliola erythrinae (black mildew), Meloidogyne sp. (root knot nematodes), Mycosphaerella erythrinae (on leaves), Nectria cinnabarina (on stems), Pellicularia kolerogna (thread blight), Phoma erythrinicola (on stems), Phyllosticta erythrinicola (leaf spot), Phymatotrichum omnivorum (root rot), Rhizoctonia ramicola (thread blight), and Verticillium sp. (probably albo-atrum) (wilt). I would hazard a guess and say it's probably Phoma erythrinicola causing the problems. Check with your county or University of California agriculture extension agent or with a local arborist who has experience with trees in your area.