Black Spots on the Underside of Schefflera
The following questions were sent to the P&PDL diagnosticians here at Purdue University:
Question: I have a schefflera that I would like to save. It has numerous black "specs" on the underside of the leaves. Several leaves are deformed (new growth) and today I noticed what appears to be tunnels in the leaves. They look kind of gold. Any ideas? Thanks for your help. By the way, I have had these for about six months and they were doing OK til now.
Answer: I will try to guess what is happening here, although without actually seeing the plant, this becomes somewhat difficult. I suspect that the black spots that you are finding under the leaves are the result of insects. Often lace bugs are the culprit, but again without looking I cannot be sure. Regardless, using insecticidal soap according to the label directions will likely take out whatever the insect is. You may find that it is necessary to treat more that once however (see label directions). Good luck !
-Tim Gibb, Entomologist