Fungus on Sago Palm
People often mistake the Cycad aulacaspis scale (Aulacaspis yasumatsui) as a fungus on the sago palm, according to the University of Florida Polk County Master Gardeners. Sago palms infested with the pest look as if they have a dusting of snow across their foliage and trunks. The white coating appears the most severe on the underside of the fronds and those closest to the base of the plant, but a heavily infested sago displays a white coating on the upper and lower surface of its fronds. Does this Spark an idea?
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History
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The Cycad aulacaspis scale insect was brought into Miami in 1996 from its native Asian homeland. The pest quickly spread throughout southern and central Florida's sago palms. The scale insects depend on the wind for dispersal. The transport of infected ornamental sago palms can also spread the pests. The insect has also invaded Hong Kong, Hawaii, and the Cayman Islands. It does not damage other garden plants or trees. The insect only occurs on the sago palm in the United States.
Appearance
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The insect invades the trunk, fronds and roots of the sago, which makes the pest difficult to kill. The scales infest the roots of the sago at depths of approximately 24 inches. The insects encase themselves in a waxy white armor covering on the surface of the sago's tissue. Under the protection of their armor, the insects suck the nutrients from the sago's tissue with their powerful mouths. As the scales multiply, the entire surface of the sago's fronds display a white coating. The infected frond eventually turns brown and dies.
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Control
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The use of systemic insecticides can prove effective at some stages of the scales lives. The University of Florida's IFAS Extension suggests that the insects metabolic activity may decrease, which makes them unable to absorb the insecticide. Fish oil emulsion and petroleum-based horticultural oil can help control the scale insects. Spray both the upper and lower parts of the sago's fronds when applying horticultural oils. Soak the ground surrounding the sago palm with the horticultural oil to a depth of 1 foot. Apply the oil once a week for five weeks to control pests.
Removal
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Even after the insect perishes, the waxy scale continues to cling to the sago palm's fronds. The white coating renders the plant visually unappealing. The scales usually begin to become infested with a fungus and may fall from the plant in time, according to the University of Florida IFAS Extension. Pruning away the heavily infested fronds does not hurt the sago palm. It also creates a more aesthetically pleasing plant. Watch the sago closely for any signs of re-infestation. If the plant becomes infested again, re-treat it using the horticultural oil.
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References
- University of Florida Polk County Master Gardeners: White Stuff on Sago Palms
- University of Florida IFAS Extension; Cycad Aulacaspis Scale, Aulacaspis Yasumatsui; T. J. Weissling, et al.
- USDA Regional IPM Centers Information System; Jody Haynes
- State of Hawaii Department of Agriculture; Sago Palm Scale; Ronald A. Heu, et al.; September 2003
