Onion Maggot

What it looks like

Onion maggots are small, yellowish-white, legless larvae. The adults are gray flies, smaller than houseflies. Onion maggots look very much like cabbage root maggots, but they prefer different plants.

There are several generations of onion maggots each year. Adults come out in early spring, mate, and usually lay their eggs at the soil line. The eggs hatch after just a few days, and the maggots burrow into the soil and feed for a few weeks. They then change into pupae in the soil or in plant roots.

Damage

Onion maggots do the most damage to early-season plantings of onions, garlic, leeks, and shallots. They feed on and tunnel through roots and bulbs, which can cause stunted growth, yellowing, wilting, and plant death. Their tunnels also leave plants open to rot diseases.

How nematodes help

The beneficial nematodes in Scanmask hunt down and kill onion maggots in the soil. Killing the maggots stops the life cycle, so new adults don't emerge.

How to apply

Treat with Scanmask from March to August, applying it along rows or around transplants. The Garden Pack includes Scanmask Spray and the Nema-Jet Sprayer.

See How to apply for step-by-step directions, or use the calculator on the Scanmask Spray page to see how much you need.