Insect Pest Alert

If you have any Eastern White Cedar on your property, you may be noticing the leaf scales look like they are dying, especially at the tips.

Cedar leafminer (Argyresthia thuiella and other species) is a tiny moth whose larval stage feeds on the inside of leaf scales, causing them to turn yellow, then brown and dead. New generation larvae are feeding inside foliage now and populations are expected to build in some areas of southern Ontario.

If you haven’t already pruned them, eastern white cedar foliage can be lightly sheared to reduce populations of larvae that would normally persist into 2019. There is no need to collect clippings because the clippings will desiccate and will not be able to support larval development.

Annual summer sheering of this evergreen hosts can, over time, reduce infestations of leafmining pests, and also create a more full look by supporting increased lateral bud growth.

(Excerpt from: ONnursery crops; IPM This Week – July 9, 2018; Time To Prune Boxwood and Eastern White Cedar; Posted on July 13, 2018 by Jen Llewellyn)