Phlox problem - Ask Extension
I live in NE Minneapolis, and love my phlox. It looks diseased this year. There is some sort of grayish debris on the leaves. I don’t see aphids, Iâ...
Knowledgebase
Phlox problem #797826
Asked June 25, 2022, 5:58 PM EDT
I live in NE Minneapolis, and love my phlox. It looks diseased this year. There is some sort of grayish debris on the leaves. I don’t see aphids, I’m Not really sure what to do. The problem started on the bottom toward the roots in the bottom of most of the plants looks like it’s dying.
Hennepin County Minnesota
Expert Response
It looks like your phlox in your first photo likely has powdery mildew. It is a fungus made worse with crowded plants. It will look terrible in the foliage but typically not impact the blooms. Control methods are to cut down and dispose of all plant material in the fall, give room around plants for air flow and/or plant varieties that are resistant.Â
The stunted growth of the plant in the second photo looks like aster yellows may be the issue. If the plant has aster yellow it needs to be dug up and disposed of.Â
Below is a link that has information on both powdery mildew and aster yellows.
https://apps.extension.umn.edu/garden/diagnose/plant/annualperennial/phlox/leavesdiscolored.html
The stunted growth of the plant in the second photo looks like aster yellows may be the issue. If the plant has aster yellow it needs to be dug up and disposed of.Â
Below is a link that has information on both powdery mildew and aster yellows.
https://apps.extension.umn.edu/garden/diagnose/plant/annualperennial/phlox/leavesdiscolored.html
