Treating Magnolia Scale - Ask Extension
I believe the magnolia tree in my yard has a widespread infection of soft scale insects. The branches are covered in white places and it feels like i...
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Treating Magnolia Scale #839169
Asked July 05, 2023, 6:27 PM EDT
I believe the magnolia tree in my yard has a widespread infection of soft scale insects. The branches are covered in white places and it feels like it is almost raining under the tree from all the "honeydew" dripping down. My car is coated in this stuff because the tree is next to the driveway where I park (see pic). We have lived here almost 11 years and I never noticed this issue before, definitely not to this degree. It is a fairly large tree so it would be impossible to spray every branch and if we tried to cut off all the affected branches, I'm not sure if anything would be left so it seems like a systemic treatment is the only option.
If the infestation is this widespread, is it worth treating or is the tree a goner? How successful would a treatment be, how long would it take, and how much would it cost? Would we be able to treat this ourselves or need to contact a professional?
thanks!
Franklin County Ohio
Expert Response
There are several wonderful websites that delineate your problem with magnolia scale:
https://ohioline.osu.edu>factsheet>ENT-61
https://hort.extension.wisc.edu>articles>magnolia-scale
https://www.canr.msu.edu>news:check_magnolias
All indicate that there are very specific windows of time when these insects can be sprayed. Summer horticultural oils can be applied in late Aug. when the crawlers have settled in. You must thoroughly wet the leaves and stems. Then you can apply it again in Oct-Nov. and in March to kill overwintering nymphs located in the stems. You can also apply an appropriate insecticide when insects are in the crawler stage (late Aug-early Sept.) You must follow the instructions on the label. Soil drenches of a systemic insecticide can provide control if applied in early May.
Regarding the size of your tree and whether it will remain viable, I suggest you contact a certified arborist. This is a decision that must be made based on an assessment of the tree itself. You can find a local arborist through treesaregood.org.
I wish you good luck in your battle against a very small insect!
https://ohioline.osu.edu>factsheet>ENT-61
https://hort.extension.wisc.edu>articles>magnolia-scale
https://www.canr.msu.edu>news:check_magnolias
All indicate that there are very specific windows of time when these insects can be sprayed. Summer horticultural oils can be applied in late Aug. when the crawlers have settled in. You must thoroughly wet the leaves and stems. Then you can apply it again in Oct-Nov. and in March to kill overwintering nymphs located in the stems. You can also apply an appropriate insecticide when insects are in the crawler stage (late Aug-early Sept.) You must follow the instructions on the label. Soil drenches of a systemic insecticide can provide control if applied in early May.
Regarding the size of your tree and whether it will remain viable, I suggest you contact a certified arborist. This is a decision that must be made based on an assessment of the tree itself. You can find a local arborist through treesaregood.org.
I wish you good luck in your battle against a very small insect!
