I've applied it, but again the flowers quickly turned brown and died. A. Camellia petal blight is a fungal disease that causes blossom rot, says UC master gardener Veronica Simpson. Brown lesions develop, with the flower centers discoloring first.
Blossoms drop prematurely.
Sanitation is the most effective control. Pick and dispose of all brown blossoms on the plant and pick up all fallen flowers. Remove old mulch and replace it with 4-5 inches of organic mulch to reduce spore survival. Avoid overhead watering, as overhead irrigation and rainy weather promote the disease. Chemical treatment to assist with the management of camellia petal blight is not recommended.