July, 2010

Northern Shenandoah Valley Master Gardener Association

16 hours ago

What's wrong with my plant? Rudbeckia Triozid psyllid nymph damage on Blackeyed Susan

Big patches of dark purple with a light green spot in the middle recently appeared on my Blackeyed Susans (Rudbeckia hirta). Last year, I also saw it on the Orange Coneflowers (R. fulgida). Though it appears to be a disease, it's actually damage from the nymph of the Rudbeckia Triozid psyllid, which feeds on the leaves.

The easiest way to deal with current issues is to remove the affected leaves and dispose of them in the trash. Unless the plant is heavily infested, it should survive the leaf removal and still bloom. Removing them this year can help reduce future occurrences. You can also treat with various insecticidal soaps. (If you choose this route, ensure you read and follow the label.)

Learn more about Rudbeckia Triozid at content.ces.ncsu.edu/rudbeckia-triozid.

See a photo of the nymph at ag.umass.edu/greenhouse-floriculture/photos/rudbeckia-psyllid-nymph

Insecticidal soap for psyllids, page 4-64 Home Ornamentals: Insects of Trees, Shrubs, Annuals, and Perennials in the "VCE Pest Management Guide for Home Ground and Animals."

Pictured: Rudbeckia Triozid psyllid damage of Rudbeckia hirta ... See MoreSee Less

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