Boxwood infection - Ask Extension
Hi,
I like to talk to expert on how to treat my boxwood plants that seems to have been infected by some kind of decease. Bottom portion is getting ...
Knowledgebase
Boxwood infection #947819
Asked October 28, 2026, 11:22 AM EDT
Hi,
I like to talk to expert on how to treat my boxwood plants that seems to have been infected by some kind of decease. Bottom portion is getting brown but still green on the top.
Oakland County Michigan
Expert Response
The webbing on the plant and browning is an indication of spider mites.
At this time of the season, it is too late for any insecticide control. Any spider mites would be in the egg life stage. With the drier weather, I would recommend keeping your plants watered to boost their health.
If you chose to use a pesticide to manage mites, early May is the critical time for application. Horticultural oil is effective. Other chemicals to consider also include abamectin (Avid), bifenthrin (Talstar), malathion or oxythioquinox (Morestan) during the first two weeks in May.
For your future questions, please either use Ask Extension or email instead of both to avoid duplication of efforts. We strive to provide an answer to all inquiries within 2 - 3 business days.
At this time of the season, it is too late for any insecticide control. Any spider mites would be in the egg life stage. With the drier weather, I would recommend keeping your plants watered to boost their health.
If you chose to use a pesticide to manage mites, early May is the critical time for application. Horticultural oil is effective. Other chemicals to consider also include abamectin (Avid), bifenthrin (Talstar), malathion or oxythioquinox (Morestan) during the first two weeks in May.
For your future questions, please either use Ask Extension or email instead of both to avoid duplication of efforts. We strive to provide an answer to all inquiries within 2 - 3 business days.
Hello,
Regards
Thank you for your response. Per your suggestion I will water the plants. Other than watering, is there anything I can apply now to control the damage? I am just worried they may not last. I will apply below recommended options in early May.
Regards
Simon
On Oct 28, 2026, at 12:52 PM, Ask Extension wrote:
You could use a hose to spray off the webbing.
I would not make other changes now. Fertilizing is not recommended, since extra Nitrogen could strengthen foliage production and boost spider mite populations at this time of year.
I would not make other changes now. Fertilizing is not recommended, since extra Nitrogen could strengthen foliage production and boost spider mite populations at this time of year.
