Coneflower – Aster Yellows vs Coneflower Rosette Mite

Q: I discovered deformed blooms on my coneflower, which I suspect to be caused by aster yellows. I immediately dug up the plant and threw it out. After more research I discovered coneflower rosette mites cause similar damage. Can you tell from this picture if my coneflower had aster yellows or did it have mites?

A: I researched the two similar phenomena and prepared a comparative list:

CONEFLOWER ROSETTE MITE
>cone has tufts, flower petals normal in shape or color
>only affects cone
>tufts/rosettes usually retain some of the original color of the cone
>looks more like fuzzy knots or bumps on the cone

Mites live inside the developing flower buds and suck nutrients from the base of the flowers. As a result, rosette-like tufts of stunted and distorted flower parts will sprout from the tops or sides of the cones.

Cutting and destroying flower heads deformed by mite activity will reduce mite populations.

ASTER YELLOWS
>foliage may have yellow mottling
>cones produce yellowish-green rosettes.
>flowers look more like vegetative growths with green tones, and the petals are typically affected
>If you have a plant that normally blooms pink and it starts showing green petals and/or cones, then it is very likely affected by aster yellows. Flower petals may appear as a ring of tiny greenish-yellow spoons arrayed around the base of highly deformed cones and the cones may appear as tightly clustered rosettes.

Spread from plant to plant by sucking insects, particularly leafhoppers.

Members of the aster family (Asteraceae), such as asters, marigolds, coreopsis and purple coneflower are commonly affected by this disease.

There are no sprays that will suppress the disease and, once plants become infected, they remain both infected and infectious. All parts of the plant, including the root system must be removed and destroyed. Pathogen cannot survive outside of the plant so the bacterium will not remain in the soil.

My diagnosis?

Aster yellows

Coneflower mites photos

Odd-looking Coneflower

Coneflower mites vs aster yellows Excellent photos!