Eriophyid Mite on Fragrant Sumac - Ask Extension
Good Afternoon!
Please see the attached photo taken on one of my properties in Baltimore County of little gall like bumps on Rhus aromatica. Am I co...
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Eriophyid Mite on Fragrant Sumac #884845
Asked September 11, 2024, 12:10 PM EDT
Good Afternoon!
Please see the attached photo taken on one of my properties in Baltimore County of little gall like bumps on Rhus aromatica. Am I correct that it is an Eriophyid Mite infestation. Is there a control or prevention that you recommend?
Thanks for your help.
Dave
Baltimore County Maryland
Expert Response
Hello Dave,
Yes, these are leaf galls caused by an eriophyid mite. That same mite species also creates similar galls on Poison Ivy. There are no preventative measures recommended, since we would not suggest using a pesticide (miticide) on the Rhus. You could rake-up and dispose of the leaves once they shed later this autumn, in case they harbor overwintering mites, but that isn't a foolproof measure since mites are so small that they can easily blow around on the wind to colonize new areas. (They also might hitch rides to new plants on bird feet.) Fortunately, despite being a bit of an eyesore (or curiosity), they are not harmful to the plant and don't need to be treated. Even so, no pesticide will get rid of them once the galls have already formed for the season.
Miri
Yes, these are leaf galls caused by an eriophyid mite. That same mite species also creates similar galls on Poison Ivy. There are no preventative measures recommended, since we would not suggest using a pesticide (miticide) on the Rhus. You could rake-up and dispose of the leaves once they shed later this autumn, in case they harbor overwintering mites, but that isn't a foolproof measure since mites are so small that they can easily blow around on the wind to colonize new areas. (They also might hitch rides to new plants on bird feet.) Fortunately, despite being a bit of an eyesore (or curiosity), they are not harmful to the plant and don't need to be treated. Even so, no pesticide will get rid of them once the galls have already formed for the season.
Miri
