Sago Palm White Spots

Asked December 13, 2012, 12:58 PM EST

I have several Sago Palms that are over 20 years old. A month or so ago they all developed white spots that look like scales and are almost completely covering the leaves. I tried spraying with malathion and later a systemic fungicide, but no luck. Do you have any suggestions?

Harris County Texas trees and shrubs plant disease horticulture

3 Responses

Sago palms can be attacked by several different species of scale and also by mealybugs. Your description sounds like it may be cycad or aulacaspis scale (Aulacaspis yasumatsui) that you are seeing but I can't know for sure without seeing a sample. If you will cut off a frond or section of a frond with the pests on it, place it in a plastic bag, secure the bag closed and then drop it off at the Harris County Extension Office at the address below we can examine it, identify the pest and prescribe a course of action to control it. There is no charge for this service.
In the absence of a postitive identification, you may have success controlling the pest with sprays of horticultural oil directed upward to coat the undersides of all fronds and the trunk. Repeat sprays weekly for a month or more. Combining the oil sprays with a systemic insecticide product containing the ingredient imidocloprid may also enhance your control efforts. However I suggest you start by dropping off a sample so we can know for sure which pest we are dealing with.

Thanks Skip, I'll start with the oil and imidocloprid. I'm in Clear Lake, is it possible that I could mail you a sample to that address?

Thanks again!