Pest identification
What's eating my courgette?
Aphids (Myzus persicae and Aphis gossypii — peach-potato and melon aphids)
Signs: Clusters on growing tips and leaf undersides; leaves curl and yellow; aphids transmit cucumber mosaic virus (CMV), causing mosaic mottle, distortion, and dramatically reduced yield
Control: Inspect weekly; blast with water; introduce parasitic wasps (Aphidius); spray insecticidal soap or neem oil; remove and bag severely virus-affected plants immediately
Slugs and snails
Signs: Seedlings and young plants eaten at soil level; irregular holes in larger leaves; slime trails evident
Control: Ferric phosphate pellets around transplants; deep mulch kept slightly away from stem; go out after dark to hand-pick; delay transplanting until plants are established (≥15 cm tall)
Whitefly (Trialeurodes vaporariorum under cover; Bemisia tabaci outdoors in warm seasons)
Signs: Tiny white moths flutter up when plant is disturbed; nymphs on leaf undersides produce honeydew leading to sooty mould; leaves yellow and weaken
Control: Yellow sticky traps to monitor; introduce Encarsia formosa under glass; insecticidal soap sprays; reflective mulches deter adults outdoors
Squash vine borer (Melittia cucurbitae) — primarily North America
Signs: Sudden wilting of entire vine; sawdust-like frass at base of stem; larvae tunnel through stem pith, killing plants rapidly
Control: Wrap lower stem in aluminium foil to deter egg-laying; monitor for orange and black moths in early summer; slit stem, remove larvae, bury stem section to encourage re-rooting; row covers until flowering
Keep courgette pest-free
Healthy plants resist pests best. Get the basics right:
Courgette pests — FAQ
What is eating my courgette?
Courgette's biggest enemy is the squash vine borer in North America and powdery-mildew-spreading aphids and whitefly in the UK and Europe. Slugs shred seedlings at germination. Cucumber mosaic virus, spread by aphids, stunts and mottles plants badly. Keep aphid populations low and mulch to deter slugs.
How do I get rid of aphids (myzus persicae and aphis gossypii — peach-potato and melon aphids) on courgette?
Clusters on growing tips and leaf undersides; leaves curl and yellow; aphids transmit cucumber mosaic virus (CMV), causing mosaic mottle, distortion, and dramatically reduced yield Inspect weekly; blast with water; introduce parasitic wasps (Aphidius); spray insecticidal soap or neem oil; remove and bag severely virus-affected plants immediately
How do I get rid of slugs and snails on courgette?
Seedlings and young plants eaten at soil level; irregular holes in larger leaves; slime trails evident Ferric phosphate pellets around transplants; deep mulch kept slightly away from stem; go out after dark to hand-pick; delay transplanting until plants are established (≥15 cm tall)
How do I get rid of whitefly (trialeurodes vaporariorum under cover; bemisia tabaci outdoors in warm seasons) on courgette?
Tiny white moths flutter up when plant is disturbed; nymphs on leaf undersides produce honeydew leading to sooty mould; leaves yellow and weaken Yellow sticky traps to monitor; introduce Encarsia formosa under glass; insecticidal soap sprays; reflective mulches deter adults outdoors
How do I get rid of squash vine borer (melittia cucurbitae) — primarily north america on courgette?
Sudden wilting of entire vine; sawdust-like frass at base of stem; larvae tunnel through stem pith, killing plants rapidly Wrap lower stem in aluminium foil to deter egg-laying; monitor for orange and black moths in early summer; slit stem, remove larvae, bury stem section to encourage re-rooting; row covers until flowering