Pest identification
What's eating my cosmos sulphureus 'klondike'?
Aphids
Signs: Clusters on shoot tips and buds; distorted growth and sticky honeydew causing sooty mould.
Control: Strong water spray; insecticidal soap or neem oil; rely on natural predators like ladybirds and hoverflies.
Thrips
Signs: Silver-grey streaking and distortion on petals and leaves; tiny dark specks (frass) visible on flowers.
Control: Remove badly affected flowers; apply spinosad or insecticidal soap; use yellow sticky traps to monitor.
Caterpillars / budworm
Signs: Ragged holes in petals and buds; buds may fail to open.
Control: Handpick caterpillars; apply Bt (Bacillus thuringiensis) spray to buds and foliage.
Slugs and snails
Signs: Seedlings eaten to the soil line overnight; slime trails on soil.
Control: Iron phosphate pellets; copper tape on container rims; hand-pick at dusk.
Keep cosmos sulphureus 'klondike' pest-free
Healthy plants resist pests best. Get the basics right:
- What eats sulphur cosmos — the species this cultivar belongs to
- What's wrong with my plant? — the diagnosis apps compared
- Common cosmos sulphureus 'klondike' problems & fixes
- Cosmos sulphureus 'Klondike' watering schedule
- Cosmos sulphureus 'Klondike' light requirements
- Full cosmos sulphureus 'klondike' care guide
Cosmos sulphureus 'Klondike' pests — FAQ
What is eating my cosmos sulphureus 'klondike'?
Sulphur cosmos 'Klondike' is largely trouble-free but aphids readily colonise the soft growing tips. Thrips rasp petals, causing silvery streaking on flowers. Caterpillars (especially Helicoverpa budworms) chew buds and flowers. In wet seasons, slugs and snails shred seedlings at ground level. Deer and rabbits will browse plants where present.
How do I get rid of aphids on cosmos sulphureus 'klondike'?
Clusters on shoot tips and buds; distorted growth and sticky honeydew causing sooty mould. Strong water spray; insecticidal soap or neem oil; rely on natural predators like ladybirds and hoverflies.
How do I get rid of thrips on cosmos sulphureus 'klondike'?
Silver-grey streaking and distortion on petals and leaves; tiny dark specks (frass) visible on flowers. Remove badly affected flowers; apply spinosad or insecticidal soap; use yellow sticky traps to monitor.
How do I get rid of caterpillars / budworm on cosmos sulphureus 'klondike'?
Ragged holes in petals and buds; buds may fail to open. Handpick caterpillars; apply Bt (Bacillus thuringiensis) spray to buds and foliage.
How do I get rid of slugs and snails on cosmos sulphureus 'klondike'?
Seedlings eaten to the soil line overnight; slime trails on soil. Iron phosphate pellets; copper tape on container rims; hand-pick at dusk.