Dear Dee, Help! We have a Magnolia tree that has a heavy infestation of Magnolia Scale. Is our tree savable? It hasn’t leaved or bloomed. We read that there is an ‘oil’ to spray on them, but no idea what to use. We have had this tree for many years so is not something that we got by purchasing an infected tree.�
I have done some research on Magnolia scale and have come to find out it is the largest scale insect found in the United States. This purple insect spends the winter on the twigs and branches of the Magnolia. It begins to feed in the spring by sucking sap and nutrients from the bark tissue. The Magnolia scale matures in August and the female lays her eggs beneath a powdery white or shiny brown shell. The young insects then overwinter inside the scale. It is possible with repeated infestations for branches to die and eventually the whole tree. Spray the Magnolia with a systemic insect control in September when the young are active. Before new growth starts the following spring spray with a dormant oil spray, also referred to as horticultural oil, to control overwintering insects. These products can be purchased at your local garden center.