California Gardening: plumeria problem, 1 by alladrm

alladrm wrote:
Already looked on the plumeria forum but didn't see any helpful info. The growing tips of my plant are constantly caked with what I think is the dried white sap they bleed when injured. Although I've been interested in gardening all my life, it's only been in the last year that I actually have the ground to do anything but containers so all this is still very new to me. I've tried insecticidal soap, neem oil, and pyrethrin to no avail. What could be causing this and what can I do about it?