Knowledgebase
Fletcher scales on my globe arborvitae? #753590
Asked June 02, 2021, 4:13 PM EDT
Hennepin County Minnesota
Expert Response
It does appear that your arborvitae have fletcher scale, as you surmised. There are several treatments available for this pest, but one is to simply do nothing. Natural predators may eliminate the pests within a few years. You might also consider the use of horticultural oil or insecticidal soap. If these fail, there are several herbicides available to kill the scales. These are most effective when applied in mid- to late-June. There is no need to trim your arborvitae further. For more information, see
https://extension.psu.edu/fletcher-scale
https://www.canr.msu.edu/news/life_cycle_and_management_of_fletcher_scale_on_taxus_and_arborvitae