Monarda flower problems

by Caroline
(Quebec, Canada)

My Monarda plants won't flower. They come up every year, nice leaves, they even flower but no petals at all. None. There are little black things around where the petals should be. Is it some kind of insects that are eating the petals and leaving that stuff behind?

Doug says You're saying that the Monarda grow well. OK. You're saying that they bud up - you can see growing buds - but that the buds don't unfold to produce flowers. All that's left is a small black balls.

Sounds like you've got yourself a somewhat rare disease called "yellows". This causes a distortion of the petals to black weird looking or non-existent petals.

Yellows is caused by microorganisms called phytoplasmas that infect the leaf and flower tissue. They are moved between plants by leafhoppers as the carrier/vector.

That's the good news. The bad news is that you're going to dig up and discard these plants. The phytoplasma are microscopic sized (smaller than a bacteria but larger than virus) and are literally impossible to control without the use of drugs such as tetracyclines.

You're also going to have to establish organic controls for leafhoppers - the main insect spreading this problem. Rotenone and diatomaceous earth will do this as soon as you see the pest because it will spread the disease from wild to cultivated plants or between cultivated plants such as Monarda and Echinacea.

Sorry to be the bearer of bad news but now you know what you have - you can move to remove and repair - then prevent it from happening again.

Good luck