How to treat scale on a magnolia tree

Asked July 10, 2018, 2:44 PM EDT

I have a magnolia tree with scale. An arborist looked at the tree and said it is very difficult to treat scale, so he recommended removing the tree and planting another variety. Do you know if there is a good way to treat the tree with high success and not spending a lot of money? Thank you Tom Arnfelt Phone-651-491-8003

Ramsey County Minnesota magnolia horticulture

1 Response

Yes it is possible to treat scale. This seems to be a year with a high incidence of Magnolia Scale. I will be giving you a link to our publication on when to treat and what to treat with but you will be able to use horticultural oil this fall and again next spring. That will smother the nymphs. Magnolia Scale is a soft scale. You may start seeing other insects and/or black mold type material. That is from the honeydew (poop) produced by the scale insects. You could use an insecticidal soap to clean that off with a strong spray of water. Here is the link. There are sections that have drop down boxes when you click on them: https://extension.umn.edu/yard-and-garden-insects/scale-insects-minnesota-trees-and-shrubs