Photinia spp.
Leaf Spots (fungi – Entomosporium maculatum, Cercospora heteromeles, Phyllosticta heteromeles): Spray at 7-10 day intervals during wet or humid weather with a recommended fungicide. Expanded, brown and often zoned spots on the leaves. The leaf spots may be round-to-irregular, purple, then gray-to-brown with purple margins in which black specks can later be found.
Powdery Mildew (fungi – Podosphaera leucotricha and Sphaerotheca pannosa): Dust or spray with approved powdery mildew fungicide when mildew first appears. Repeat at 10-14 day intervals as long as necessary. Preventive sprays in following years would produce better control.
Cotton Root Rot: (See the section on Cotton Root Rot)
Mushroom Root Rot: (See the section on Mushroom Root Rot)
Root Knot Nematode: (See the section on Root Knot Nematodes)
Fire Blight (bacterium – Erwinia amylovora): Leaves, stems and fruit are blighted by this bacterium. New shoots suddenly appear as if scorched by fire. Brown or blackened leaves cling to twigs. Slightly sunken, girdling, discolored cankers develop on twigs, branches and trunk. Follow the same control procedures recommended for pears.