Magnolia scale

Asked June 23, 2020, 8:32 AM EDT

I’m in Dimondale, Michigan. Last summer I had a severe infestation of scale on my mature magnolia. Sprayed with neem oil, then malathion and ultimately did a soil drench in late August. The third week of April I performed an an additional imidacloprid drench. Yesterday, 22 June, I noticed small, oval (1/16th-1/8th inch) fuzzy, white, mobile insects crawling on the branches of the magnolia. In appearance they mimic adult scale but are very mobile. My compound question is: are these scale “crawlers”? If so is my April drench sufficient to eradicate them or should I spray or drench again? Thank you for your help, Dan

Eaton County Michigan

2 Responses

The white fluffy and "very mobile" insect in your photo is probably the larva of a lady beetle (Coccinellidae). They are eating the scale insects and I would not recommend treating the tree at this time because it would harm the lady beetles and other beneficial insects. Later this summer or in the fall, you can use an insecticidal soap or horticultural oil spray to kill the crawlers that will be emerging at that time. To learn more about timing your magnolia scale management I would recommend reading these MSU Extension articles:
https://www.canr.msu.edu/news/check_magnolias_for_magnolia_scale_now
https://www.canr.msu.edu/news/why-is-sap-dripping-from-my-magnolia-tree
And you can learn more about the lady beetles and other scale insect predators from this Ohio State University Extension page: https://bygl.osu.edu/node/1316

Thank you. That’s very helpful.
Dan