All my coneflowers are developing a strange wilting of the leaves (see attached photo) nearest to the flower cone. All the lower leaves appear healthy, though some leaves also have purple spots. Any ideas what may be causing this? Thank you.
it's probably aster yellows - it could also be botrytis blight. not much in the way of treatment for either - especially in canada as things are so restricted there now. i posted yesterday about botrytis http://www.botanicalgarden.ubc.ca/forums/showthread.php?t=53356 if it's aster yellow, not much you can do at all. it's recommended to remove the plants completely since it's transmitted by leaf hoppers - they eat one plant that's infected and go to another one for their next meal and leave the pathogen behind to infect that one. i had it a few years ago and just cut off what ever was affected (flower heads and some part of the stalks) and they came back the next year without any indication of the disease still being there and i've not seen it since (now watch, since i said that, they'll all have it again! :) )
