This will provide some control if untreated camellias aren't too close. Use of PCNB sprayed on soil surface which prevent apothecium development. Cause - abiotic disease associated with drought and salinity. This is often associated with over use of fertilizers. Symptoms - interveinal and marginal necroting spotting spotting of young foliage.
Some distortion is associated as well.
Symptoms - erratic but intense mosaic of leaves, white variegation of flowers. Control - none. Often the variegation is regarded as desirable, even leading to a new variety. Plant injury is minimal. The virus spreads only by taking cuttings from infected plants as there is no known vector.