Onion Maggots: A Common Pest of Onions and Their Kin
Onion maggots are tiny, white larvae that can cause significant damage to onions, leeks, shallots, garlic, and chives. They are the larval form of a small, gray fly that resembles a housefly.
Identification
Onion maggots are about 1/4 inch (6 mm) long and have a cream-colored body. They infest the bulbs of onion family plants, creating tunnels that can weaken the bulbs and make them susceptible to rot.
Life Cycle
Onion maggots have three generations per year. The first generation is the largest and causes the most damage. The adults emerge in the spring and lay their eggs in the soil around onion plants. The eggs hatch into maggots, which feed on the onion bulbs for about three weeks before moving to the soil to pupate. The adults emerge from the pupae in about two weeks and begin the cycle again.
Damage
Onion maggot damage can include:
- Poor germination and survival of young plants
- Limp, yellow leaves in older plants
- Soft rot of the bulbs, both before and after harvest
Control
Cultural Control
- Crop rotation: Avoid planting onions in the same location year after year. Onion maggots only feed on members of the onion family, so rotating your crops can help to reduce their population.
- Remove and destroy infested plants: If you find any onion plants that are infested with maggots, remove them from your garden and destroy them. This will help to prevent the maggots from spreading to other plants.
- Remove crop debris: At the end of the growing season, remove any remaining crop debris from your garden. This will help to reduce the number of overwintering onion maggots.
Chemical Control
Insecticides are generally not effective against onion maggots because the maggots are protected inside the onion bulbs. However, there are some systemic insecticides that can be effective if applied early in the season, before the maggots have infested the bulbs.
Prevention
The best way to prevent onion maggot damage is to use a combination of cultural and chemical control methods. By following these tips, you can help to protect your onion plants from this common pest.
Additional Tips
- Keep your garden clean and free of weeds. Weeds can provide shelter for onion maggots and other pests.
- Water your onion plants regularly, especially during dry spells. Onion maggots are more likely to attack stressed plants.
- Fertilize your onion plants according to the package directions. Healthy plants are more resistant to pests and diseases.
- Inspect your onion plants regularly for signs of infestation. If you find any maggots, take steps to control them immediately.
By following these tips, you can help to keep your onion plants healthy and productive.