Cause The fungus Alternaria alternata has been shown to be involved with this problem. Frequently observed on the cultivar Moorpark in eastern Washington and occasionally on cultivars Perfection and Riland. Symptoms may be due to a hypersensitive host response to fungal infection. Sometimes called frog spot in California.
Symptoms Superficial red spots on the surface of fruit with smooth to only slightly sunken light tan to brown centers and bright red halos. Similar to disorders caused by San Jose Scale or the shothole fungus.
Chemical control Broad spectrum fungicides may be effective when used for other problems.
Reference Larsen, Jr., R.P., Covey Jr., H.J., and Fischer, W.R. 1980. A red spot fruit blemish in apricots. Phytopathology 70:139-142.