Pest identification
What's eating my dahlia 'penhill watermelon'?
Slugs and snails
Signs: Emerging shoots shredded or lost overnight; irregular holes in mature leaves at soil level.
Control: Wildlife-safe ferric phosphate pellets; beer traps; encourage ground beetles and hedgehogs.
Earwigs
Signs: Large blooms with tattered, nibbled petals; earwigs hiding inside the flower centre.
Control: Straw-filled inverted pot traps on canes near plants; remove earwigs into soapy water at dawn.
Aphids
Signs: Soft tip growth smothered in colonies; distorted buds; honeydew promotes ants and mould.
Control: Strong water jet; insecticidal soap or neem oil; ladybirds and hoverfly larvae as biocontrol.
Caterpillars (various moth larvae)
Signs: Large irregular holes in leaves; rolled or tied leaves hiding larvae; damage worst mid-summer.
Control: Hand-pick and destroy larvae; Bacillus thuringiensis (Bt) spray on foliage; check plants weekly.
Keep dahlia 'penhill watermelon' pest-free
Healthy plants resist pests best. Get the basics right:
Dahlia 'Penhill Watermelon' pests — FAQ
What is eating my dahlia 'penhill watermelon'?
Dahlia 'Penhill Watermelon' is a large decorative dahlia whose big blooms are a haven for earwigs. Slugs and snails attack new shoots, aphids mass on tips, and caterpillars of various moths will chew leaves if present. Slugs and earwigs are the twin threats most dahlia growers battle all season.
How do I get rid of slugs and snails on dahlia 'penhill watermelon'?
Emerging shoots shredded or lost overnight; irregular holes in mature leaves at soil level. Wildlife-safe ferric phosphate pellets; beer traps; encourage ground beetles and hedgehogs.
How do I get rid of earwigs on dahlia 'penhill watermelon'?
Large blooms with tattered, nibbled petals; earwigs hiding inside the flower centre. Straw-filled inverted pot traps on canes near plants; remove earwigs into soapy water at dawn.
How do I get rid of aphids on dahlia 'penhill watermelon'?
Soft tip growth smothered in colonies; distorted buds; honeydew promotes ants and mould. Strong water jet; insecticidal soap or neem oil; ladybirds and hoverfly larvae as biocontrol.
How do I get rid of caterpillars (various moth larvae) on dahlia 'penhill watermelon'?
Large irregular holes in leaves; rolled or tied leaves hiding larvae; damage worst mid-summer. Hand-pick and destroy larvae; Bacillus thuringiensis (Bt) spray on foliage; check plants weekly.