Allium insubricum · Bulb
Allium leaf miner: Bag foliage after flowering to trap emerging flies or lift bulbs in autumn to remove pupae.
Onion white rot: Remove and burn infected plants immediately; avoid replanting alliums in the same soil for many years.
Onion downy mildew: Improve air circulation and avoid overhead watering; remove severely affected foliage promptly.
Onion fly: Use insect-proof netting over plants during peak flight times in spring and late summer.
Bulb rot: Ensure planting sites have excellent drainage and avoid watering during dry spells if soil is heavy.