Won’t a spray solution of soap and water wipe out the fungus?
Depends upon the fungus. Some virii winter-over in the dead debris collecting underneath the plant; others are systemic and are ingrained in the plant, so they need a systemic chemical to deal with the fungus.
All debris should be cleaned-up from under the tree, affected blossoms removed asap, and disposed of, and plant treated after disease is ID’d.
Camellias have a lot of disease and insect problems, especially in the south where cold doesn’t kill the bugs and disease. Up north, cold winters take care of bugs and disease.
http://www.clemson.edu/extension/hgic/pests/plant_pests/shrubs/hgic2053.html
&
http://www.weekendgardener.net/plant-diseases/camellia-flower-blight-030703.htm
The soap and water treatment usually works well on live insects, but not on diseases.
Neem oil sometimes works:
http://en.wikipedia.org/wiki/Neem_oil