Pensacola News Journal

For: Saturday, Oct. 19, 2002

By: Daniel E. Mullins

Extension Horticulture Agent

Santa Rosa County

A New Sago Pest to Watch For

Better check your sago palms. There is a newly imported scale insect that is running rampant on Cycad species in south Florida and has been found as far north as Tallahassee. There is danger of it moving into Northwest Florida, and it might even be here already.

This pest is commonly known as the Cycad aulacaspis scale. The scientific name is Aulacaspis yasumatsui Takagi.

This species of armored scale was originally described from Cycad specimens collected in Bangkok, Thailand in 1972. It was first found in Miami, Florida during 1996. King sagos were found to be heavily infested at that time. The Fairchild Tropical Garden and Montgomery Botanical Center were within the initially infested area.

The Cycad aulacaspis scale is not only moving fast in Florida, but has recently been reported in Hong Kong, Hawaii and the Cayman Islands. Although scale insects may spread short distances by wind dispersal of young crawlers, the long distance spread is probably through the transport of infested plants.

Gardeners who grow sagos and other Cycads are advised to inspect plants closely. Report any new or unusual scale to your local agricultural official. If this scale has moved into the northern coastal counties of Florida, it should be confirmed.

Damage of infested plants first appears as chlorotic spots, but most of the fronds later become brown and dried out. Highly infested cycads become completely coated with a white crust that includes both live and dead insects. The insects favor the lower leaf surfaces, and in light infestations might not be found on upper surfaces. Up to 500 scales per square centimeter have been found on highly infested plants.

Individual scales are white and tend to be pear shaped. Two different sizes are seen, because the female is larger, at about one and one-half millimeter in diameter, while the male is about half as large. There are two other less damaging scale species that are also commonly found on sagos, so make sure to obtain positive identification.

Scientists are busy developing control measures for this new pest. Though several insecticides show promise, the most consistently effective treatment has been spraying them with horticultural oils. Both fish oil emulsion and petroleum-based oil products have been used with good results.

The number of times that infested plants must be sprayed has not yet been determined. Since scales have also been found up to 15 centimeters deep on roots, repeated sprays will be necessary.

Watch for more information about this aggressive new scale insect. It moves fast and is a sago killer.

The following web site provides more details about the cycad aulacaspis scale: http://creatures.ifas.ufl.edu/orn/palms/cycad_scale.htm.