The plumeria I started from a cutting did very well during the summer months, but now the tips of the branches have a gluey like substance on the part where the new leaves are forming.. The leaves never develop. The just dry up. It is slightly sticky and transparent. I don't see any insects or scale. I don't want to lose this plant Thanks ,Denise
The sticky substance is likely honeydew, which is the secretion of pests.
Several pests are common to Plumeria including Spider Mites, Aphids, Mealybug, Scale and Whitefly.
Neem Oil is a good treatment for all of these sucking insects.
Here are some links with more information.