white growth on lantana camara stems
Our Lantana camara has a "white powdery" growth on the stems, also white discoloration under some leaves. It is spreading to other Lantana bushes also.
Certified GKH Gardening Expert
This is likely Powdery Mildew.
It can be common if conditions are damp or poor air circulation.
Here is a link with more information and how to treat the plants.