Now this isn’t a pretty sight, is it? You try so hard to grow native plants for the wildlife and you wind up getting the wrong kind of wildlife–something eating the flowers!!!
Well, don’t despair. Although these flowers don’t look pretty, their wildlife value is still intact–it’s the brown “cones” in the middle that are actually the “flowers”–the purple-y pink petals, or rays around the edges are just there to provide attraction and a better landing surface.
As you can see in this photo, the flower has lost all its rays, practically, and yet the tiny sweat bee that’s landed on it is just bright yellow with the pollen it’s harvesting. So all is not lost.
There are actually several things that could be eating the coneflowers but in my garden I saw them last year when they were on my black-eyed susans (rudbeckias). For years my black-eyed susan leaves would get some sort of blackish mottling on the leaves that I always thought was a fungus. It affected my golden oregano too.
Then last year I was working in the garden and I brushed the golden oregano and something flew out! So I investigated closer and found a small beetle that looked very similar to a cucumber beetle, but with slightly different markings. All my bug books didn’t have just exactly that but in it, but I was able to isolate the family to the leaf beetle or chrysomelid family.
This is the family that gives us all the baddies: cucumber, asparagus and potato beetles, the lily leaf beetle, and the flea beetle.
Because these beetles are so hard to spot, and because they fly, control is difficult. It’s not as if you can just knock them into a cup of soapy water as you can with Japanese beetles. I just tolerate the damage because this is a wildlife garden and I do not want to use anything, even an organic control, that might affect the bees.
A chemical control, particularly a systemic, is most likely your best bet against these should you be willing to go that route. But remember, you are growing native plants that will be visited by birds, bees and butterflies so consider carefully whether you wish to use a systemic that will be eaten by everything that feeds on this plant!
By the way, Japanese beetles also eat coneflowers and black-eyed susans–but I’m convinced if you had those, you’d know it. They’re not hard to spot!