Orlando Sentinel: Beloved plants under attack

Orlando Sentinel

Date: Sunday, November 19, 2006 Section: A SECTION
Edition: FINAL Page: A1
Source:Kumari Kelly, Sentinel Staff Writer

Tiny bug puts a big bite on sagos
Cycad scale is fast killing off one of the state’s most popular landscape
LAKELAND — Tom Broome considers himself a scientist, and he’s frustrated.
His latest experiments target a killer bug that threatens to wipe out
Orlando’s sago population in the next decade or so.

With the way things are going, his frustration mounts.
“Forty percent to half [of king sagos in Orlando] are already gone,” said
Broome, owner of The Cycad Jungle in Lakeland and president of The Cycad
Society, an organization with members worldwide. “Orlando has spread
faster than any city I’ve ever seen.”

In South Florida, 80 percent of the popular landscape plants are already
dead, and the destructive insects responsible for their demise have
marched northward into Central Florida homeowners’ yards. The pests are
even showing up halfway across the world, threatening some of the sago’s
cousins, which include some of the world’s most endangered plants.
Broome is one of the nation’s top experts on cycads — the family of flora
that includes the king sago, which is often called a palm but is not —
and he’s battling cycad aulacaspis scale, or CAS. Also known as Asian
cycad scale, the tiny insect began attacking Florida’s sago population in
1992, when it was brought into the Miami area from Southeast Asia.
In just a few years, the insect — which shows itself as a white powder on
the leaflets and trunk of the sago and even infests the root system — has
cost the state’s nursery industry millions of dollars, officials with the
University of Florida say.
Homeowners, seeing the white powdery appearance but unaware of its
damaging effects, often leave their infected plants untreated, resulting
in a rapid spread to neighboring sagos or repeat infestations. Those who
do recognize the problem might be just as likely to rip the plants up
rather than go through treatments that can take months and aren’t always
King sagos normally are easy to care for. That’s why they — with thick
trunks topped by dark-green fronds covered with thin, pointy leaflets —
are among the most common landscape plants around.
Cycads, all of which are endangered in the wild and date back to the time
of dinosaurs, will grow nearly anywhere: on the edge of a rocky cliff, in
sand and in places where nothing else will grow. Even the endangered ones
are bred and grown in nurseries such as Broome’s.
“This [scale] has taken a nice, low-maintenance plant and turned it into a
nice, high-maintenance plant,” said David Shibles, the resident
horticulture extension agent in Polk County. He says he gets about 20
calls a month as well as walk-in traffic related to the sago problem.
“It’s probably the No. 1 question I get,” he said.
The tiny insect, which can be blown miles by the wind and can crawl across
the ground to neighboring plants, multiplies so quickly it can cover a
sago in weeks and kill a single specimen or an entire forest of cycads in
a year’s time. That’s what happened in Guam in 2003, when the bug made its
way there.
Experts think the insect likely piggybacked aboard sagos shipped by
Florida’s plant-export industry to a hotel district in Guam.
The scale doesn’t discriminate — it attacks both nursery-grown
ornamentals and wild cycad populations — and it has few natural enemies.
Once attached to a plant, it literally sucks the life out of it, feeding
on sap until there’s nothing left. Layers of dead scale will pile on top
of each other, creating the powdery white appearance.
Alternatives available
With his world-renowned collection of 30,000 plants, which include 180
species, Broome has spent more than 15 years experimenting on cycads.
Varied soil mixtures, different container sizes, re-sexing males and
females — the veteran nurseryman has done everything imaginable to his
cycads. He has purposefully infected them with scale and sought solutions
for years. He’s still working on it.
Scientists at the University of Florida are also working to find new
chemicals and new natural ways to prevent scale. Tiny parasitic wasps —
about the size of the tip of a pen — have been released with some
success, although some experts think they are not aggressive enough to
keep up with the rapidly multiplying scale.
Treatment — using repeated applications of horticultural oil and
insecticides — can be time-consuming and may be unsuccessful. For
homeowners who want to replace their sagos, there are alternatives —
though they’re not cheap.
One is the cycad Dioon edule, commonly known as virgin palm, which is
about the same size and shape as a king sago but is more cold-hardy,
Broome says. He sells a specimen in a 25-gallon container for $125.
Another cycad choice might be an Encephalartos ferox, which has
holly-shaped leaflets and can grow to a 10-foot spread. It is known for
colorful cones in the middle and is becoming popular in South Florida. A
large one — 4 feet tall and 6 feet across — will cost about $400.
Some landscapers suggest Phoenix roebelenii, known as the pygmy date palm,
which runs $100 for a 3-foot plant at Clark’s Nursery in Kathleen. A
30-gallon sago there is $125.
Owner Ron Clark said he fields about 100 calls a week on the sago issue;
many callers wind up opting for new plants. And Clark warns that many more
will likely need them.
Said Shibles, the Polk extension agent, “If it’s not treated, it will
Illustration: PHOTO: Tom Broome
PHOTO: Steve Lochman of Davey tree service looks for signs of scale Friday
on a king sago in downtown Orlando. `Forty percent to half are already
gone,’ says Tom Broome, owner of The Cycad Jungle in Lakeland.
PHOTO: Cycad aulacaspis scale, or CAS, is an insect that attacks the
leaves, stems, trunks and even the root systems of sagos.
Spray infested plants with horticultural oil (such as summer oil, volck
oil or dormant oil), fish oil or malathion in oil every other week until
scale insects are gone.
Drench soil around the plants with a systemic insecticide, which will move
into the plants’ sap system and poison the insects.
Consider replacements not affected by scale, including Dioon edule and
Encephalartos ferox, both cycads; Zamia furfuracea, known as cardboard
plant; and Phoenix roebelenii, commonly called pygmy date palm.
Experts think that in 10 years, most of the king sagos in Central Florida
will be gone. The culprit is a scale insect that feeds on sap until the
plant whithers and dies. It also attacks the root system.
Around the world
The insects have been found in many places, including the Caymand Islands,
Puerto Rico, the US Virgin Islands, Hawaii, Georgia, Texas, Alabama,
California, Louisiana and South Carolina.
1992: Scale insects arrived in South Florida.
2006: The insects have killed 80% of the king sagos in South Florida;
about 40% have been killed in Central Florida.
2003: Infested plants from Florida introduced.
2006: Infestation widespread.
SOURCES: Montgomery Botanical Center, USDA.


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