Fungus Diseases of the Camellia

Petal Blight

• Petal blight is an aggressive disease that is most active during the damp, humid periods of spring. The camellia’s infected blooms develop tiny brown spots that grow into larger brown and yellow spots. Though the infected blooms appear wilted and decayed, the dried petals remain intact and defoliate from the camellia. The infected blooms carry additional fungal spores that cause secondary infections to the camellia and surrounding vegetation.

Sooty Mold

• Sooty mold is a cosmetic fungal disease that attacks the surface of the camellia’s foliage. The spores of this airborne disease attach to the honeydew that accumulates on the foliage. The honeydew develops as a result of insects feeding on the foliage. The infected leaves develop dark-colored fungal threads, or mycelium, across the surface. Although this fungal disease does not damage the foliage, the mycelium prevents air and sunlight from reaching the leaves. This lack of light and air causes the camellia to experience growth stunt, dieback and wilt.

Leaf Gall

• Leaf gall infections are most prominent during the spring months. The fungal spores target the camellia’s young foliage causing it to develop into thick, distorted leaves with a pinkish-green color. The underside of the leaves hold white layers of spores that cause secondary infections. Once the spores are released, the infected foliage wilts and blackens before defoliating from the camellia. Though unsightly, leaf gall infections do not cause severe harm to the camellia.

Canker

• Canker is a detrimental disease that gradually kills the camellia. Favoring the cool, wet periods of spring and fall, these spores infect the camellia through its wounds. The camellia’s foliage becomes dull and yellowed before wilting and turning reddish brown. Cankers develop around the branches, stems and base of the shrub. The cankers slowly girdle and strangle the areas, causing dieback and growth stunt.

Root Rot

• Phytophthora root rot is a long-living, soil-borne disease that can live for several years in the soil without a host to infect. This disease targets the camellia’s vascular system and infects the shrub through its root system. The infected vascular system becomes restricted and unable to move water and nutrients throughout the shrub. The camellia’s leaves become dull and discolored before wilting and falling from the shrub. The infected shrub also experiences loss of vigor and dieback until the camellia is overwhelmed from the infection and dies.

Care

• Keep the camellia’s planting area free of debris and defoliation to keep the fungal spore population down. Treat infections immediately upon first signs of infection. Remove all diseased areas from the shrub with sharp, sterile shears. Always sterilize the shears between each cut to prevent spreading the infection to healthy areas. Discard diseased clippings in the trash. Do not use the clippings for mulch and do not burn, as these actions can spread disease to healthy shrubs and shrubs. Spray the pruned camellia thoroughly with a fungicidal treatment. Apply the fungicide according to the package's directions to prevent further injury to the camellia.