Pest identification
What's eating my sweet black-eyed susan?
Aphids (Uroleucon rudbeckiae and U. leonardi)
Signs: Dense colonies on flower stalks and stems cause wilting, yellowed foliage and sticky honeydew; sooty mould may follow.
Control: Blast off with a strong water jet; apply insecticidal soap for heavy infestations; plant alyssum or yarrow nearby to attract ladybirds and parasitic wasps.
Slugs and snails
Signs: Irregular ragged holes in leaves and chewed stems at ground level, especially on young plants; slime trails confirm the culprit.
Control: Apply iron phosphate slug pellets around the base; use a gritty bark mulch deterrent; hand-pick at night during damp spells.
Sawfly larvae
Signs: Skeletonised patches where larvae strip leaf tissue, leaving a papery window before progressing to full holes.
Control: Pick off larvae by hand; spray with pyrethrin or insecticidal soap; beneficial wasps parasitise sawfly pupae, so avoid broad-spectrum insecticides.
Keep sweet black-eyed susan pest-free
Healthy plants resist pests best. Get the basics right:
Sweet Black-Eyed Susan pests — FAQ
What is eating my sweet black-eyed susan?
Sweet Black-Eyed Susan (Rudbeckia subtomentosa) is a tough prairie native with few serious pest problems. Aphids — especially Rudbeckia-specialist species — are the most common nuisance, clustering on flower stalks below the cone. Slugs can damage young stems and foliage. Beneficial predators such as hoverflies and minute pirate bugs naturally colonise the plant and help keep pests suppressed.
How do I get rid of aphids (uroleucon rudbeckiae and u. leonardi) on sweet black-eyed susan?
Dense colonies on flower stalks and stems cause wilting, yellowed foliage and sticky honeydew; sooty mould may follow. Blast off with a strong water jet; apply insecticidal soap for heavy infestations; plant alyssum or yarrow nearby to attract ladybirds and parasitic wasps.
How do I get rid of slugs and snails on sweet black-eyed susan?
Irregular ragged holes in leaves and chewed stems at ground level, especially on young plants; slime trails confirm the culprit. Apply iron phosphate slug pellets around the base; use a gritty bark mulch deterrent; hand-pick at night during damp spells.
How do I get rid of sawfly larvae on sweet black-eyed susan?
Skeletonised patches where larvae strip leaf tissue, leaving a papery window before progressing to full holes. Pick off larvae by hand; spray with pyrethrin or insecticidal soap; beneficial wasps parasitise sawfly pupae, so avoid broad-spectrum insecticides.