Archontophoenix alexandrae
Photo by Dennis Lutge
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Asian Cycad Scale Emergency Control Suggestions
It seems those who are finding they have Asian cycad scale are at a loss as
what to do to save their favorite king or queen sago palms. There are
conflicting reports as to how to control the insects. Even landscapers who
once found the king sago to be a virtually trouble free plant are now at a loss
as to what to do when the homeowners ask them to tend to the problem. We
have considered here several options and are now prepared to suggest a treatment
regiment.
1) Determine rather or not you have the Asian scale.
This should be easy to identify. The Asian scale differs from magnolia scale in
that it seems to always start in the fuzzy part of the crown, the trunk or near
the roots. Early infestations are hard to determine except magnolia scale
is much less likely to start in these locations. About 28 days after
initial infection of the sago, then you start seeing the eggs hatch and millions
of crawler scales moving from the crown up the leaves of the sago, at first the
stem of the individual leaves are nearly coated white. A definite
clue that you have Asian scale is the speed at which it can multiply. Once the
first egg batch hatches a clean sago palm can get so many scales on the stems of
leafs that the stem can show up white in photographs. The crawlers also
can move inches per day rather then inches per month as with magnolia scale. You
can also see small long/thin pin shaped "male" scales all over which
typically outnumber the females dramatically.
2) Cut and remove ALL leaves on the sago. Be careful in this
leaf removal process that you do not shake up scales to be blown in the wind. It
is in your best interest not to allow the scales from your plants to spread to
others in your yard or to infect neighbor's plants. Carefully bag all the
leaves, do not carry them to the dump loose in an open trailer or back of pickup
truck. This will spread them all over town and then the war against these pests
will be lost. The best option is to try to burn them. If burning is not an
option, Asian cycad scale does not infect other plants. You can find a location
30 feet or more away from your sago and bury the leaves.
3) Spray or coat the trunk, crown and soil with oil. Seems
the pest can be smothered to death by spraying cooking oil, horticultural
oil (available at better lawn and garden centers) or fish emulsion oil has also
been shown to be effective. You may need a dial and spray sprayer and
follow the directions on the label. It seems approximately 5 fluid
ounces per gallon is the mixing rate, to make the oil mix with water use some
type of dishwashing liquid squirted in the sprayer "and" it is a
pretty good idea to mix either malathion 50 or diazinon so that both the oil and
pesticide spray on at their individual suggested rates per gallon. The
suggested rate is about 1 quart per sago palm although some indications are this
is ignoring scale that could be in your soil in the roots of the plant, so you
may want to give the soil a really good soak down with the mix. The treatments
will need to be repeated every two weeks, if you are getting heavy rains of
summer, retreat weekly. This is only a short term immediate fix just to
contain your own damage to your palm and to prevent spreading your insects to
others in the yard or neighborhood. Treatment with oil should be used for about
3 months and then you can discontinue as long as neighbor's plants don't appear
to be infested and you have no signs of infestation yourself.
4) Inform your neighbors about Asian Cycad Scale. Show them
what to look for and give them treatment advice. Identification and
treatment is the best thing we can do to beat Asian Cycad Scale. Unlike Citrus
Canker, this pest can be cured. The idea is get your neighbors to cure their
plants as well so they will not re-infect your plants later.
5) Long Lasting Systemic Pesticides. In Tampa its
not certain the war against the pest is completely lost. There is a good chance
Tampa's much colder then Miami winters will harass the insects. We stand a
better chance of controlling the pest. After the initial response with oil
and rapid kill pesticides, systemic pesticides like imidoclopid, sygon or
orthene will help buy you more time between treatments and in effect, make the
entire plant poisonous to anything that tries to feed upon it. Imidoclopid
seems to be the longest lasting, lasting up to 4 months between treatments and
is the treatment of choice at Fairchild Tropical Gardens in Miami (in the middle
of the worst infested area of the state). Systemics also prevent
reinfestation from a neighbor's infested plant by never allowing wind
blown scales to establish and feed upon your plant.