Aster Yellows? - Ask Extension
Newly planted (this season) echinacea cultivars are showing signs of mal-formation of flowers but do not have leaf discoloration. Species echinacea (...
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Aster Yellows? #841648
Asked July 20, 2023, 10:00 AM EDT
Newly planted (this season) echinacea cultivars are showing signs of mal-formation of flowers but do not have leaf discoloration. Species echinacea (widely planted throughout the yard) show no signs of deformed flowers or leaf discoloration. Phlox in the same bed as the affected echinacea cultivars have been experiencing leaf dieback and discoloration and small, sparse blooms. Can you confirm Aster Yellows on the two echinacea plants? Is the phlox showing symptoms of Aster Yellows as well and should I remove them?
Prince George's County Maryland
Expert Response
It has been a brutal year for new plantings as it has been hot and very, very dry, with multiple weeks of 'severe' drought conditions reported in central Maryland. Even nurseries with dedicated watering were having pots and plants dry down very quickly and sustaining damage.
It is impossible to say for sure, but without more defining symptoms we'd not declare it to be aster yellows at this point in time.
Here is our page on Aster Yellows disease to see more:
https://extension.umd.edu/resource/aster-yellows-disease-flowers
We wonder if the symptoms are more likely from a mite (much less serious than a.y.) that can bore into the flower heads. The Ohio State link at the bottom of the page above will show you what to look for.
As for your Phlox, that looks most like some heat damage and probably mites, which are sucking insects that tend to be worse when it is hot and dry. Look closely under the leaves, which is where they stay. Here is more about them:
https://extension.umd.edu/resource/spider-mites-flowers-and-groundcovers
I was able to get pretty good control of them on my phlox by aiming a good water stream to the undersides of the leaves earlier in the season.
Christine
It is impossible to say for sure, but without more defining symptoms we'd not declare it to be aster yellows at this point in time.
Here is our page on Aster Yellows disease to see more:
https://extension.umd.edu/resource/aster-yellows-disease-flowers
We wonder if the symptoms are more likely from a mite (much less serious than a.y.) that can bore into the flower heads. The Ohio State link at the bottom of the page above will show you what to look for.
As for your Phlox, that looks most like some heat damage and probably mites, which are sucking insects that tend to be worse when it is hot and dry. Look closely under the leaves, which is where they stay. Here is more about them:
https://extension.umd.edu/resource/spider-mites-flowers-and-groundcovers
I was able to get pretty good control of them on my phlox by aiming a good water stream to the undersides of the leaves earlier in the season.
Christine
Awesome answer. Thank you!
You're welcome! Have a great weekend.
