Don’s Expert Answers: Frangipani trunks have black soot

Question From:
James Daly in Bali, Bali International

Nature of problem:
Frangipani trunks have black soot

Type of Plant (if known):
Mature Frangipani…10 + yrs old

Symptoms of Plant Illness (please try NOT to diagnose your problems yourself):
Black soot on trunks

Soil Type (e.g. sandy, clay or loam) OR Potting Mix Type:
limestone

How often do you water the plant:
once a week

How many hours of sunlight does the plant get each day:
10

How long since you planted it:
10 yrs +

Have you fertilised? If so, with what and when:
yes…general fertilizer

Is the plant indoors or outdoors:
outdoor

Is the plant in a pot or in the ground:
ground

What other treatments have you given the plant:
Neem

Upload photo if available:

Other Comments:
The trunks seem to have a black soot forming. When you touch it, its quite sooty and very dark.

Answer:
Hi James. A photo would have helped a lot. My guess is that you have Frangipani rust. If frangipanis are deciduous in Bali, just ignore the sooty mould on the trunk. If the leaves are yellowish with golden dots underneath, maybe spay with mancozeb plus…but I would just ignore it. Don