Black sooty mold on my camellia
One of my camellias has black sooty mold (exactly like the photo on the Timber Press Web site of 5.31.2012). It is a large bush (about 8 feet tall) and seems to get morning and afternoon sunlight, depending on the season. The mold is not on all the leaves, mostly on the shadier side of the plant and more of the leaves at the bottom of the plant than at the top. The flowers are gorgeous currently. I see no evidence of ants but do see evidence of small, white, soft, cocoon-like things on the back of some of the leaves. How can I get rid of this problem? Should I cut back some of the infected branches to increase the amount of sunlight into the plant's interior? What is neem oil, and should I use it? Thank you in advance for your response.
Douglas County Oregon
Sounds like you have some Cottony Camellia Scale. When they feed on the lower side of leaves they produce a honey like substance that drips onto lower leaves. Then the sooty mold grows in the honey dew. The best time to control the scale is in late summer to early fall. Use either a horticultural oil or the Neem oil you mentioned. They are both registered organic pesticides. Don't use them if the temperature is above 85 degrees, you can get leaf burn. The sooty mold does not do any damage to your plants but can be washed off the plant with just soapy water and a sponge when the weather warms up. Then just rinse off the soap with more water.
Thank you. I bought Neem oil today. I am planning to wash off the plant's leaves today and then spray it with the Neem oil. You said that late summer or early fall is best for treatment, but I am afraid to let the problem progress for 6 more months without doing anything. It is in the 50's and sunny this afternoon, so I hope doing some treatment today is OK.
The insect pests are probably not active on your plant at this time. That's why I suggested you just wash off the leaves with soapy water and rinse and if you need to treat again the insects are active in mid to late summer.