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iowa_flower_nut

Here's some interesting info....

iowa_flower_nut
16 years ago

I sent an e-mail about my deformed coneflower buds (aster yellows?) to the extension service with Iowa State University. I sent the same picture I posted here and asked about re-planting and if Aster Yellows contaminated the soil. Here's the response I rec'd. Thought some of you might be interested. Too bad I've already pulled most of the coneflowers! ~ ~ ~

Before you dig up the purple coneflowers, you may want to clip off 2

or 3 of the affected flower heads and send them to the Plant

Diagnostic Clinic at Iowa State. The aster yellows-like symptoms

could also be due to a tiny mite. The mite feeds inside the

developing flower head, causing it to become deformed. The mite is

so small that a microscope is needed to see it. If it turns out that

mites are responsible for the deformed flower heads, the plants don't

have to be destroyed. You simply clip off and destroy all of the

affected flower heads. Tips for submitting samples to the Clinic can

be found at the following web

site. http://www.plantpath.iastate.edu/pdc/node/217

If aster yellows is responsible for the deformed flowers, the plants

will need to be dug up and destroyed. Aster yellows is caused by a

tiny organism called a phytoplasma, similar to a bacterium. The

phytoplasma is carried from plant to plant by aster leafhoppers,

which feed on the sap of the plants. The phyoplasma does not exist

in the soil. Aster yellows resistant plants can be planted in area

as soon as the purple coneflowers are dug up and destroyed.

I would probably leave the Rudbeckias at this time. I'm not

convinced that they have aster yellows. I would wait and see how

they perform next year.

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