THE PUBLIC IS ASKED TO OBSERVE THE
QUARANTINE OF BRINGING PHOENIX PALMS INTO
RIVERSIDE AND IMPERIAL COUNTIES
Urban growth has increased movement
of ornamental palms into area causing
renewed concern to California Date Industry
RIVERSIDE, CA. – (September 6, 2006)
One of the most destructive palm diseases
in California landscapes, Fusarium
oxysporum, commonly known as Fusarium
wilt, a fungus deadly to palms, may be
coming from quarantine areas into the
Coachella valley and other protected areas.
The public is asked to observe the
quarantine on the Phoenix variety of palms
still effect throughout all of California.
The tremendous increase of urban growth and
landscaping projects throughout Riverside
county has increased the number of
ornamental palms coming into the Coachella
Valley, causing the California date industry
some renewed alarm.
“An increasing movement of
ornamental palms into the Coachella Valley
is causing concern that possible diseased
palms or soils infected with Fusarium
oxysporum may be coming from the
quarantine area into protected areas,” said
Angela Godwin, Deputy Agricultural
Commission, County of Riverside. “There is
no known cure for Fusarium oxysporum;
only preventative measures can be taken to
protect healthy date plantations.”
The Date Palm Disease Interior
Quarantine, established by the California
Department of Food and Agriculture to
protect the California date industry, has
been in effect since 1980. The quarantine
“prohibits the movement of all genus Phoenix
plants and parts for propagation” into
protected areas including Imperial,
Riverside (east of Cabazon) and a portion of
Inyo counties.
“The California date industry is
the second largest agricultural commodity in
the Coachella Valley. Ninety-five percent of
domestic dates are grown in this valley,”
said Lorrie Cooper, manager of the
California Date Administrative Committee
that operates under a USDA marketing order
which oversees the quality of dates grown in
California.
“A contamination of Fusarium
oxysporum would be devastating to the
California date industry. We urge all
homeowners, homeowner associations,
commercial landscapers and nurseries to
observe the quarantine. Help protect this
important industry – and your own landscape
investments -- by making sure no one brings
Fusarium oxysporum infected trees
into the protected area.”
“Infected trees, especially
those that show no symptoms, could pose
grave danger to the commercial date industry
as well as to home and commercial landscapes
containing palms,” said Godwin.
“Landscapers, homeowners and nurseries
should be able to verify their source of any
variety of Phoenix palms purchased, or face
having the palms confiscated and possible
criminal charges brought forward in an
effort to protect the California date
industry.”
Anyone purchasing any species of
Phoenix palms should be aware of the
quarantine and are required to verify that
the palms in their inventories or possession
were grown inside the Coachella Valley or
other protected areas.
The soil-borne fungus can cause
Fusarium Wilt, a fatal disease that attacks
and kills both young and mature palm trees.
Attacking the plants’ vascular system
through its roots, Fusarium oxysporum
causes uneven blockage which results in
gradual, uneven wilting and eventually
death.
The quarantine requires that all
tools (saws, knives, etc.) used for trimming
or pruning palm trees be sterilized.
Fusarium oxysporum can
easily be spread by common pruning practices
and through infected offshoots, palm
fragments, fronds, manure, soil and even
through symptom-less hosts such as Pygmy
Date palms (Phoenix roebelinii) – a
common ornamental palm. Once in the soil, it
is spread by irrigation water passing
through infested fields causing contact
between healthy and diseased roots.
Fusarium oxysporum
persists in the form of chlamydospores in
dead tissues of diseased plants that are
released back into the soil where they can
remain dormant for eight years or longer.
Even small numbers of the chlamydospores are
sufficient to restart the disease of only a
few roots.
According to Dr. Harry
Donselman, a palm specialist in Murrieta,
CA., “There is evidence that the disease
can be spread by infected soil if ornamental
palms were grown at a nursery with infected
Canary Island Date Palms (Phoenix
canariensis). The disease could be
spread to the containers of these plants.
It is important that we maintain and enforce
the state interior quarantine restricting
uncertified movement of Phoenix palms into
the Coachella Valley.”
During late 1800s, a disease
similar to Fusarium Wilt called Bayoudh
Disease caused a major epidemic and was
responsible for wiping out some 12 million
date trees in Morocco and Algeria. It still
continues to kill up to 12 percent of date
palms per year in those areas, according to
a scientific report by the European and
Mediterranean Plant Protection Organization
(EPPO).
The epidemic caused destruction
of more than half the commercial date trees
decimating the industry from 300 to 400
healthy trees per hectare to 40 to 50
poor-yielding palms per hectare. Control of
Bayoudh Disease depends on strict internal
quarantine measures, according to the
report. (to view report:
www.eppo.org/QUARANTINE/fungi/Fusarium_oxsp_albedinis/FUSAAL_ds.pdf.)
A new form of the disease, (Fusarium
oxysporum f.sp. canariensis) was later
found on the Canary Islands and was reported
in Italy, France, Japan, the Canary Islands
and California between 1973-1977. Its
distribution in California includes Los
Angeles, Orange, Riverside, Sacramento, San
Bernardino, San Diego, San Mateo and Santa
Barbara counties. Phoenix palms may not
come in from these areas.
For a fact sheet detailing the
Date Palm Disease Interior Quarantine,
please visit on line at
www.DatesAreGreat.com. To report
suspected Phoenix palm quarantine
violations, please call the Riverside County
Agricultural Commissioners Office, District
Supervisor Keith Selnick in Indio at (760)
863-8291or Deputy Agricultural Commissioner
Angela Godwin at (951) 955-3015.
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