As you suspected the hoppers do have more than a little to do with it, as they spread a bacteria-like mycoplasma organism that causes a disease called Aster Yellows. It effects different plants in different ways, but for echinacea, it causes the flowers to turn green & leathery, sterile & malformed, which on echinacea can look rather pretty & interesting, if only it weren't a spreading disease. Other indicators on other plants include flattened elongated leaves that get yellow streaks; leaves aging to rust colored; or stunted growth.
Semi-amusingly, in one gardening bulletin board, someone announced they had a new "mutation," & the other posters on the board began begging for starts of it for their own gardens. It was necessary to register to post there, & since nobody knowledgeable would be likely to bother to sign up for the privilege, those folks just kept begging for starts of the infected plants.
It is spread by the leafhoppers from a reservoir plant that is probably a common weed, possibly of the onion family; but if you live near vegetable plantations (carrots, onions, lettuce, wheat, potato, parsnip, alfalfa), or commercial flower fields (asters), the disease especially likes single-crop areas & is spread from there by the leafhoppers.
I would dig up & compost infected plants (when WELL composted there'll be no lingering mycoplasma organisms; if your composting technique is iffy, then bag & toss infected plants). Then replace them since the soil itself is unaffected. But if leafhoppers remain numerous they'll continue to bring in the disease.
There is no cure & the key is controlling the leafhoppers (though aphids may also spread it). Commercial crops deal with it by doing rotational crops & not planting infected crop choices for two or three years & by spraying harsh chemicals to kill leafhoppers -- but insecticides usually make a problem worse in the long run, this being a short-term fix that also kills beneficial insects which would have done a better on-going control, but when poisoned permit the leafhoppers to return in following years in greater numbers. In their soft-bodied larval stage they can be managed with soapy water the same as for aphids, a treatment that is far less hazardous to beneficial insects.
Organic control of leafhoppers: They winter over in garden rubble, so clean up the garden, & don't winter-mulch with leaves or straw until the population is controlled. Release ladybugs. Also, places like
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sell lacewing eggs cheaply & lacewing larvae ("aphid lions") expensively, & lacewings are the natural enemy of aphids & lacewings.
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also sells pirate bugs -- it is rare that a garden with plenty of lady bugs, aphid lions, & pirate bugs have major aphid or leafhopper problems. You've probably seen the pirate bugs in your garden & not recognized them, they are like hard beetles with a diamond patterned back, & a pointy snout; they are gardeners' best friends. Unfortunately they're ghastly expensive to buy, but lacewings & ladybugs are cheap enough.
It looks like Aster Yellows. Aster yellows is caused by a tiny organism known as a phytoplasma and is spread from plant to plant by leafhopper feeding. Once infected, there is no cure. Diseased plants should be promptly removed and discarded to reduce further spread. sed5555
Now you're scaring me. I have shrubs, which I think are chinese barberry that have leaves that age to rust ... not all the leaves, just a few. Could it be just plain old rust of some sort?
LOL. That's more than semi-funny. I've seen the results of vectored viruses, courtesy of the spit bugs, so that's why I suspected a virus. I didn't know about phytoplasma 'til just now. Fascinating.
There's farmland within 15 miles ... and many many common weeds nearby.
I killed all the ones on the echinacea manually, right after I took the pictures. But I do have some every year, and usually on the wild black currants.
I pulled the affected echinacea this afternoon and put them into the municipal compost bag today. Their mountain gets hotter than my two heaps.
Soapy water and diatomaceous earth, as well as manual dispatching are my usual methods. I garden organically, so there are lots of bugs, both good and bad.
Yes. I'm sure this is the problem. That bed has poor, humus-deficient soil and I've been ammending it by leaving a thick carpte of maple leaves on it for the past few seasons, and then left it on for mulch. It has helped the soil, but I guess I won't be doing that this fall.
I had zillions of them. They seemd to have hibernated at the base of the plum tree. They've done a great job of controlling the aphids on the plum, and other aphid favourites. I wish they had an appetite for sawfly larvae. Had a plague of those this year too.
I did a search and, yes, I have seen them, though not that many. I don't kill any bugs until after I've ID'd them. I don't know that I've ever seen a lacewing in the garden.
Thanks for the information. I googled phytoplasma because I'd never hear of it before. Very interesting. One site mentioned that Tetracycline would cure a plant:
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of symptoms and even curing a plant can be achieved through the application of the antibiotic tetracycline (which is also a way to tell if you have a phytoplasma!) (McCoy and Williams 1982)
I wouldn't get antibiotic for echinacea, but it might be useful for rarer specimens. I wonder how one would use it? As a foliar spray?
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