UF/IFAS Sarasota County Extension
Horticulture

Cycad Aulacaspis Scale
(aka Asian Cycad Scale)

By Mark Shelby, Former Urban Horticulture Extension Agent

January, 2002

Have you noticed a new visitor to your landscape? One that makes your Sagos look white? This is the Cycad Aulacaspis Scale (Aulacaspis yasumatsui), also sometimes called the Asian Cycad Scale, an invasive exotic pest which completely covers Sagos and other exotic members of the Cycad family, and eventually kills them. So far, there are few reported cases on Coontie (Zamia floridana) and Cardboard Plant (Zamia furfuracea), so these are still doing fine.

These small white scale insects come in two different shapes and sizes: the males are narrow, rod-shaped and smaller, the females are round, volcano-shaped and much larger. Both are the same species of scale. This pest infests the fronds, the entire trunk, and the lower trunk and roots to six inches deep in the soil, resulting in a Sago which is covered in white from top to bottom. These pests were apparently accidentally introduced from Thailand to the Miami-Dade area in 1996. They do not have any natural enemies here and are rapidly spreading out of control over Florida. They first showed up in Sarasota County last year. A lot of people are trying all kinds of mixes, concoctions and home remedies, and are still losing these valuable plants. Some pest control companies have stopped treating Sagos and others are charging extra for this service.

This pest will force us to make a drastic choice: do we work every week or two to kill these pests, or do we simply remove our Sagos and plant something else? So far, research shows that management of this pest requires very rigid adherence to one particular method.

 

• Treat with oil. Make an application of horticultural oil (such as in UltraFine Oil) or fish oil (such as Organocide) to the entire plant - top and bottom of fronds and entire trunk.
• Remove dead scale insects. A couple of days later, or the day before re-treatment, remove dead scales clinging to the plant. This can be done with a strong water blast (from a hose-end spray nozzle) or by physically removing the scales from the fronds and trunk with a brush. If the layer of dead scales remain on the plant, then newly hatched scales will simply re-colonize the plant and will be protected from the treatment by the dead scales.
• Re-treat with oil. Seven to ten days following the first application, make another application of horticultural oil or fish oil.
• Repeat Steps 1-3 as necessary until the pest is controlled. Sometimes, it may be necessary to use a systemic insecticide to help, but this will not work by itself. Check to see of the scales are dead by scraping the scales: if they smear, they are still alive; if they flake off they are dead.
• Monitor the Sago on a weekly basis to detect future infestations, then practice steps 1-3 to prevent total take-over by the pest. Avoid using high rates of nitrogen fertilizer of the Sago and surrounding landscape or lawn. Nitrogen encourages growth flushes which are very tasty to the pest and speeds their infestation. If fertilization is required, use a light application of slow-release, low nitrogen fertilizer. Fertilize infrequently.
• Removing the infested fronds will not manage this pest, it will only hasten the decline and death of the Sago. Relying on systemic insecticides alone to control this pest will usually fail. This scale travels on the wind, so it will re-colonize from neighboring yards, as well as from the upper root system of infested plants.

Until a natural enemy arrives from Thailand to eat this pests people may stop planting Sagos or will need to work much harder or pay much more to manage the pest. To see pictures and to learn about how to manage this pest, visit the University of Florida Extension’s "Featured Creatures" website at http://creatures.ifas.ufl.edu/orn/palms/cycad_scale.htm, or call the Sarasota County Extension Hort Help Desk at 861-9807 and talk to our Master Gardeners and Horticulturists.