What can I do to stop a cottony camellia scale infestation on my large holly tree?
My large holly tree, possibly a rare variety, has what looks like a cottony camellia scale infestation. What can I do to stop it? It is seriously harming the tree--this is the third season of infestation. I am looking into spraying with horticultural oil or soap, and trying to locate a source for vedalia beetles (Rodolia cardinalis), which are documented as particularly effective for cottony scales. There are plenty of convergent ladybugs (Hippodamia convergens) for sale online, but I am having trouble locating vedalia beetles.
The scale has moved its way up the tree, the major infestation is now in the middle tier of the tree, about level with the second story of the house. The lowest level of foliage has been quite affected, there are lots of branches without leaves. The tree has been losing many leaves. I have clipped away reachable branches with signs of scale, but it is difficult to access the main problem. I am also not sure which method to use, as stated above. Please advise! Would someone from the society be willing to visit? My neighbor told me this holly tree was classified as a rare variety years ago by someone from the society. I would be so grateful for your help. We are located in center city, Philadelphia. Thank you very much.
The scale has moved its way up the tree, the major infestation is now in the middle tier of the tree, about level with the second story of the house. The lowest level of foliage has been quite affected, there are lots of branches without leaves. The tree has been losing many leaves. I have clipped away reachable branches with signs of scale, but it is difficult to access the main problem. I am also not sure which method to use, as stated above. Please advise! Would someone from the society be willing to visit? My neighbor told me this holly tree was classified as a rare variety years ago by someone from the society. I would be so grateful for your help. We are located in center city, Philadelphia. Thank you very much.
Answer
Oh what a situation. Penn State recommends a hoticultural oil, but if you use it, do it ASAP, because the recommendation is that it be used before much growth takes place in the spring. I would also recommend that you consult with a registered arborist, also as quickly as possible, to see how much pruning might be necessary to save the tree. Good luck.