What's eating my nasturtium?

Nasturtiums are notorious aphid magnets — they are often planted deliberately as a trap crop. Black bean aphids and peach-potato aphids blanket stems and leaf undersides by midsummer. Caterpillars of the large and small white butterflies (cabbage whites) also target nasturtiums. Slugs damage seedlings. Their very attractiveness to pests makes them useful companion plants when grown near brassicas.

Entire stems and leaf undersides coated in colonies; leaves curl; honeydew and sooty mould on surfaces; plants can be overwhelmed. Squash small colonies by hand; blast off with water. Accept some infestation if using as a trap crop away from other plants. Insecticidal soap works well for heavier infestations.

Holes of varying size in leaves and flowers; frass visible; young caterpillars skeletonise leaf undersides before eating through. Hand-pick caterpillars and egg masses (yellow cigar-shaped eggs on undersides); apply Bacillus thuringiensis (Bt) spray. Check plants daily during summer.

Seedlings and young plants rasped at soil level; irregular holes in leaves with slime trails overnight. Use iron phosphate pellets around young plants at transplant time. Remove daytime hiding spots (stones, debris) near beds.