Oedema

You'll see oedema on camellia leaves as watery blisters or galls, usually on lower leaf surfaces. These lesions turn brown, corky, and roughened, sometimes resembling rust or bacterial infections. This physiological condition occurs when soil moisture is high and air temperatures are lower than soil temperatures. Reduce humidity and soil moisture when possible. Maintain proper fertility to help plants resist oedema development.

Reduce storage or growing humidity or soil moisture, if possible. Maintain proper fertility for the plant being grown.