We ’ve been getting a few calls of late from northern gardeners wondering if their coneflower have aster yellows . That ’s one option — the other is an Eriophyid hint infestation . Here ’s what you need to know about thesetwo plant problem .
Aster Yellows
This disease is fairly common and can take place on many plant life , including tomatoes , marigolds , snapdragons , even lettuce , but it ’s most often noted here on coneflower . The works will show signboard of decline , such as stunted increment or damage to the leave . But the most dramatic symptom is the unhinged , deformed bloom on the plant . The plant may have growths out of its cone or tuft of green where the regal petals should be . The growths can be very foreign looking . I ’ve even catch coneflowers with flower petal develop out of the center of their strobile !
Purple cone flowers infected with aster yellows.Photo courtesy of the University of Minnesota Extension
Aster yellowsis make by a phytoplasma that is spread to the plant life byaster leaf hoppers , when they run on the plant life . The disease tend to be morecommon during blistering years , which would explain why we ’re find out more about it this year .
Aster yellows is not curable and it can circulate , so the best matter to do is remove the diseased plant and give it away . Do not summate it to your compost . If you have several coneflowers and only one or two are record symptoms , do n’t move out the others , but keep an eye on them next season for signs of trouble .
Eriophyid Mites
There are many types oferiophyid mitesand they can cause avariety of gall and growthson plants . The most common one on coneflower is the coneflower rosette mite . It ’s phone that because it produces a rosette like outgrowth on the retinal cone of the coneflower . The growth may be gullible and may even send up shoots similar to aster yellow .
The mites are microscopic and hold out inside the flower bud as it develops , soak up nutrient from the plant life . The cone of the coneflower often stock the rosette and petal around the rosette may fade . To cover for eriophyid mite , remove the flowers and do not compost . you’re able to treat plant with ahorticultural fossil oil or a miticide before bud break . For now , the best treatment is to remove the septic bloom and clean house up the garden well come crepuscule .
Side - by - Side Comparison
For an fantabulous side - by - side comparison with picture of aster yellowness and eriophyid speck on coneflowers , tick off outthis pagefrom Ohio State University .
Learn more inNorthern Gardener®magazine…
Four seasonal issues full of grow tips and featured gardens — write and edited by local northerly horticulture pros just for you .
