Allium porrum · Bulb
Slugs and snails: Use physical barriers like copper tape or crushed eggshells, and hand-pick pests at night.
Onion white rot: Remove infected plants immediately and avoid growing alliums in that soil for at least 10 years.
Leek rust: Improve air circulation and remove severely affected leaves; rotate crops annually.
Downy mildew: Ensure good drainage and avoid overhead watering to keep foliage dry.
Leek moth: Protect plants with fine insect-proof mesh during peak adult activity in spring and autumn.