American Boxwoods – White Triangle On Leaves

Q: A few of my American boxwoods have a small, triangular white
thing on some leaves; when magnified there is a small pink dot near the top of
the triangle. It can be scraped off with a fingernail. 

A: I bet it is false oleander scale. This sap-sucking insect attacks boxwood,
magnolia, aucuba, oleander, ivy, and many other plants. Heavy infestations
can cause leaf loss and general decline of the infested plant. Since immature
crawlers are present throughout the year, this scale does not have an optimal
timing for insecticide applications. Several applications of horticultural oil or
other insecticide may be necessary to reduce heavy populations. My advice is
to be hawk-eyed and prune out any affected branches on your boxwoods. With
luck you can control the pest without resorting to spraying.