Holly Bush with Scale
Hello, I have had trouble with scale on my holly bush in the past and this year, I see the bumps again on the stems. Thanks to your website, I think the diagnosis is cottony taxus scale. It is not the stage with the white cottony bumps under the leaves, but right now I see the creamy colored bumps on the stems. Can you tell me how to treat this and when? I have some neem oil and horticutural dormant oil spray. Thank you
Montgomery County Maryland
The creamy colored 'bumps' on the stems of your holly tree are most likely Indian Wax Scale. It is important that you monitor their development carefully and regularly in order to determine the optimum time to spray. We have reports that some eggs have been found in Howard County. Every week or two, pull off some of the female scales and examine for eggs and crawlers. When all eggs have hatched, usually in mid-July, spray the shrub thoroughly with a dilute (summer rate) horticultural oil (not dormant rate) to kill the crawlers before they are completely covered with white wax. These scales can also be be controlled by applying a systemic insecticide, such as imidacloprid, as a soil drench.
Thank you for the information. I attached a photo to aid in the diagnosis. I really think this is cottony taxis scale and wondered if you agree. If so, does the recommendation change?
You are absolutely correct. These are Cottony Camellia Taxus Scale insects. We erroneously assumed that it was too early for this species of scale to be on the stems. They typically begin on the underside of the leaves and then migrate to the stems. As for the proper treatment, the same regimen applies, although, for this species of soft scale, it is important to spray the infested plants with dormant oil during the winter/dormant season