Does your purple coneflower look odd?  Do the flowers look more green than purple?  Do you have satellite flowers growing out of the center of the main bloom?  If you answered yes to any of these questions there is a good chance your plant is infected with Aster Yellows.

Aster yellows is a caused by a bacteria-like organism called a phytoplasma.  Aster yellows affects over different species of plants found in 38 families.  Some of the plants that we see infected are coneflowers, goldenrod, coreopsis, carrots, and potatoes.  Once the plant is infected with aster yellows it cannot be cured and the plant should be removed.  The phytoplasma is vectored by leafhoppers from plant to plant.  Because the way the leafhopper feeds insecticides provide very little control.  A leafhopper spits and sucks at the same time so when it inserts its mouth part it can transmit the pathogen.

So what can you do?  Make sure that you only purchase plants that are not showing any signs or symptoms of the disease.  If any of your asters start to look funny error on the side of caution and dig them out.  Make sure that you clean any tool used to prevent accidental transmission.  We are also seeing a great occurrence of aster yellows on some of the new Echinacea introductions.  Also, avoid buying any of the newer introductions that bloom green.  This makes it next to impossible to monitor for the disease.

This slideshow requires JavaScript.

Scott Evans

Scott Evans is a horticulture assistant with Nebraska Extension in Douglas-Sarpy Counties. A certified arborist through International Society of Arboirculture and Nebraska Arborist Association. Scott is also Tree Risk Assessment Qualified through ISA. Scott co-leads the Master Gardener program in Douglas & Sarpy counties. Along with volunteer management he provides his expertise with disease and insect identification, lawn and landscape weed management, plant health, and I.P.M. practices. He also enjoys growing many houseplants ranging from African violets to cacti and succulents. Scott has two Bachelors of Science, one in Biology (emphasis in Botany, Ecology and Environmental Science) and second in Environmental Geology from Northwest Missouri State University. He earned his Master of Agriculture from the University of Nebraska-Lincoln.