Magnolia Scale

Magnolia scale, a significant pest for magnolia trees, has become increasingly common in Lapeer, Michigan. This insect, scientifically known as Neolecanium cornuparvum, is one of the largest scale insects in the U.S., with females reaching up to half an inch in size. They primarily infest star magnolia, saucer magnolia, and other related species.

Identifying Magnolia Scale
Magnolia scale appears as large, grayish-white bumps on the branches of magnolia trees. These insects feed on the sap, excreting a sticky substance called honeydew, which can lead to sooty mold growth on leaves and nearby surfaces. This not only affects the tree's health but also attracts other pests like wasps and ants.

Managing Magnolia Scale

Effective management of magnolia scale in Lapeer landscapes involves both cultural and chemical strategies, through a Plant Health Care Program. A Plant Health Care program is an Integrated Pest Program (IPM), designed by your Arborist that determines which seasonal insects and diseases your landscape is prone to, and sets up an insect control program.

• Cultural Control: Regular inspection of your trees for signs of magnolia scale is the 1st step in proper management. Often populations can grow to damaging levels without being noticed. Therefore, pruning out heavily infested branches can help reduce the population. Ensuring proper tree health through adequate watering and fertilization can also make trees less susceptible to severe infestations.

• Chemical Control: Spring and/or Fall spray treatments with horticultural oil offer a good level of control. Systemic insecticides can be effective when applied as a soil injection. This allows the insecticide to be absorbed by the roots and distributed throughout the tree.

Magnolia scale insects in Lapeer usually start hatching in August. In the late summer as the insects enter the crawler stage and are actively “crawling”, a contact insecticide can be applied. This contact insecticide could be applied a couple times throughout the fall to ensure adequate coverage of the susceptible young magnolia scale insects.

https://www.ipmimages.org/browse/subthumb.cfm?sub=8282&cat=46#:~:text=Whitney%20Cranshaw%2C%20Colorado%20State%20University%2C%20Bugwood.org