Onion Maggots — Organic Prevention & Treatment

Type

Insect

Severity

High

Peak Season

Spring

Plants Affected

3

How to Identify Onion Maggots

Small white maggots that bore into onion, leek, and shallot bulbs, causing rot and plant death. The adult is a small gray fly that lays eggs at the base of allium plants. Infestations can destroy entire onion crops.

🔍 Yellowing and wilting onion/leek tops

🔍 Plants pull up easily with rotted, mushy base

🔍 Small white maggots (about 1/3 inch) inside the bulb

🔍 Soft, rotting bulbs with brown tunnels

🔍 Small gray flies hovering near allium plants

🛡️ Organic Prevention

The best defense is prevention. These organic methods help keep onion maggots from becoming a problem in the first place.

🌿 Cover onion beds with floating row covers at planting to exclude adult flies

🌿 Rotate allium crops — don't plant in same spot for 3 years

🌿 Mix alliums with carrots (the scents help repel each other's pests)

🌿 Wait until soil is warmer to plant (avoid cool, wet soil)

🌿 Remove all onion debris after harvest

💊 Organic Treatment

If onion maggots are already present, these organic treatments can help get them under control without synthetic chemicals.

🧪 Apply beneficial nematodes to soil at planting time

🧪 Remove and destroy infested plants immediately

🧪 Use yellow sticky traps to catch adult flies

🧪 Sprinkle diatomaceous earth around plant bases

🧪 Consider growing onion sets instead of seeds (larger plants resist better)

Plants Affected by Onion Maggots

Onion Maggots commonly affects these garden plants. Click any plant for its full growing guide.

Bulb Onions 90–120 days · Summer Leeks 90–120 days · Summer Shallots 90–120 days · Summer

Frequently Asked Questions

How do I get rid of Onion Maggots organically?

Apply beneficial nematodes to soil at planting time Remove and destroy infested plants immediately

What causes Onion Maggots in the garden?

Small white maggots that bore into onion, leek, and shallot bulbs, causing rot and plant death. The adult is a small gray fly that lays eggs at the base of allium plants. Infestations can destroy entire onion crops.

How do I prevent Onion Maggots?

Cover onion beds with floating row covers at planting to exclude adult flies Rotate allium crops — don't plant in same spot for 3 years

What plants do onion maggots affect?

Onion Maggots commonly affects Bulb Onions, Leeks, Shallots.

Is onion maggots harmful to my garden?

Yes, onion maggots is a high-severity pest that can cause significant damage to affected plants. Early detection and organic treatment are important.