How do you get rid of Magnolia Scale?
Question:
I have a huge and beautiful, mature magnolia tree. For the first time, it’s covered with Magnolia scale and is dripping sticky liquid everywhere! I’m not sure how to get rid of it and hope you have a suggestion.
Answer:
I’m sorry to hear about your magnolia tree scale. Here’s a great fact sheet on the insect and an excerpt below that focuses on logical next steps at this stage of the season. Timing is critical, as most topical insecticides will only be effective at the crawler stage.
For a tree this size, you may want to consider hiring an arborist with a pesticide applicator license. It might be more practical to go with a systemic product applied in May if the problem persists.
SUMMER AND DORMANT OILS
Horticultural oils, often called summer oils, at the label rate applied after the crawlers have settled in late August can be very effective in reducing the scale population. Be sure to thoroughly wet down the stems and leaves. Dormant oils can be applied in October through November and again in March to kill the overwintering nymphs located on the stems. Be sure to check the spring buds, as some damage may be caused on the flower buds if they have begun to swell.