Heavily infected plants may experience premature yellowing and leaf loss. are an attractive evergreen shrub or small tree often overlooked in other parts of the country. A The most common cause is sooty mould, a fungus with dark spores which lives on the sugary substance excreted by sap-sucking insects, usually on the leaf undersides, such as cushion scale.Control the insects and wash affected leaves. Juanita Popenoe, UF/IFAS. I have tried washing it off with lukewarm soapy water, but to no avail. Camellias (Camellia spp.) Algal leaf spot (Cephaleuros virescens) shows up as silvery-grey, green, or tan raised spots or blotches with green margins that are located on leaves. Look out for colonies of aphids and scale insects on shoots and beneath leaves. The infection can spread down the petiole and into the branch, leading to dieback. It is worth knowing that Camellia leaf spots often colonise other small spots on the leaves that have been initially caused by overwatering or nutrient imbalances. Clear up any infected plant debris from the base of the plant too. Q Why are my camellia leaves covered with black marks?. If it is only a few leaves then you can probably just pick them off and destroy them. are an important feature in an all-season garden. How to Get Rid of Bugs & Fungus on Camellias. Affected cuttings may decay completely; N.B. Prevention of Sooty Mold on a Camellia. In wet or very humid conditions these may be seen to exude a black tendril of spores; Infected leaves often fall prematurely. For the past two years my camellia has had a sort of black soot on some of the leaves. Algal leaf spot on camellia. Wildly popular in the South, camellias (Camellia spp.)