|
 Frangipani rust is recorded
from Australia, Bahamas, Barbados, Canada, Colombia, Cuba, Guatemala,
Honduras, Indonesia, Hawaii and mainland USA, Mexico, Panama, Puerto Rico,
Venezuela and many countries in the Pacific. (Farr et al. n.d.) The
Plumeria genus is thought to have originated in Central and South America
and the earliest recording of the rust is from Guatemala (Kern 1907)
Distribution in
the pacific region
C. plumeriae has
been recorded from American Samoa, Cook Islands, Fiji, French Polynesia,
Guam, Samoa, Solomon Islands, Tokelau, Vanuatu, Wallis and Futuna.
Host range and
pest status
C. plumeriae
has only been
recorded from hosts in the genus Plumeria (Family Apocynaceae)
including the following species: P. acuminata, P. acutifolia,
P. alba, P. clusioides, P. rubra, P. obtusa, and
P. variegata. (Farr et al. n.d.)
Symptoms and
Signs
 Leaves become
necrotic when infected with frangipani rust. With severe infections, leaves
fall from the trees prematurely. The rust does not infect the flowers. On
the top side of the leaf, angular sunken grey-coloured lesions with dark
brown margins and yellow halos can be seen. Rust can be identified by
looking at the underside of the leaf. You will see small orange or orange
pustules. These can also occur on the topside of the leaf, but not as
frequently. These pustules break open and millions of rust spores are
released to infect nearby trees.
Description,
biology and ecology
The rust is believed
to have spread throughout the Pacific in the past twenty years, by means of
long range aerial dispersal, blowing on the wind from country to country.
While this is possible, infected frangipani cuttings have also probably been
moved between the various countries in the Pacific.
Control
measures
A number of control
measures can be applied to manage frangipani rust. The first is to remove
fallen leaves and burn them, this prevents the fallen leaves from being a
source of new inoculum. Infected leaves can be removed from the trees and
burned (or destroyed by burying or other method). Use of triadimefon (Bayleton)
has been promoted by plumeria nurseries in the US and it is reported to be
effective. The USDA currently has a project that includes screening
Plumeria germplasm for rust resistance:
http://www.ars.usda.gov/research/projects/projects.htm?ACCN_NO=407182.
There is also a report of Verticillium lecanii being used as a biological
control against the rust (McMillan 1986).
The Singapore hybrids (P.
obtusa) are more tolerant of the disease than the hybrids of the red
plumeria (P. rubra). Plumeria pudica is said to be resistant.
Phytosanitary
Measures
 AQIS requires methyl
bromide fumigation for cuttings of frangipanis or transfer in tissue
culture. |
