The initial symptoms of flower blight are small, brown spots on the flower petals. These spots can rapidly enlarge to blight the entire flower. Blighted flowers will fall to the ground or sometimes remain attached to the plant. When these conditions occur during the camellia blossom period, the sclerotium produces a fruiting structure, which releases spores that can infect the open camellia blossoms. Controlling flower blight takes two courses of action.
Sanitation is the first and most important step.
Raking up all fallen blossoms from under the plants and removing any blighted flowers remaining on the plant will get rid of most of the sclerotia that will produce fungal disease spores in the following year. Early next fall, replace or replenish the mulch around camellias with three to four inches of new mulch, which will remove or bury any of the sclerotia that remain on the ground from the previous year. Because of the way it spreads, this disease requires community-wide attention. Fungal spores are produced over the length of the camellia flowering season, from late winter through spring, and they can travel one-half mile or more from the source. It is a good idea to educate your neighbors about this and encourage them to pick up and discard or destroy diseased flowers.