See:
Holly (Ilex spp.) - Red Leaf Spotting
Cause Many commercial holly plantings have incipient boron deficiency. PNW soils west of the cascades are naturally low in boron. Many crops in these areas need supplemental boron.
Symptoms Irregularly shaped, reddish or purplish spots on the upper leaf surface; on the lower surface, spots look water soaked. As leaves age, spots enlarge and develop a pattern of concentric rings bordered with yellow. Veins enlarge, and defoliation sometimes accompanies spotting. Pitting of the upper leaf surface also may occur. Leaves appearing near the end of a growth flush may be misshapen and malformed.
Control Applying 0.1 lb actual boron to soil in fall around each tree has been effective in 10-year-old plantings. Younger trees require correspondingly less.
Reference Roberts, A.N., Ticknor, R.L., and Compton, O.C. 1961. Boron deficiency evident in Oregon holly orchards. Plant Disease Reporter 45(8):634-635.