How To Get Rid of Cabbage Maggots

In severe infestations, the damage caused by cabbage root maggots can result in complete crop failure. It is important to monitor for the presence of cabbage root maggots and implement control measures when necessary to reduce the damage they cause to crops and support the health of your garden.

What is Cabbage Maggot?

Cabbage maggot is a type of fly (Delia radicum) that is a serious pest of cruciferous crops such as cabbage, broccoli, cauliflower, and other members of the Brassica family. The larvae of the cabbage maggot, also known as the cabbage root maggot, feed on the roots of the plant, causing significant damage and reducing the growth and yield of the crop.

The adult fly is gray and about 1/5 inch long. It lays eggs near the base of the plant, usually in the soil or on plant debris. The eggs hatch into larvae (maggots), which burrow into the plant’s roots and feed on the roots for about 2-3 weeks. The larvae then pupate in the soil, forming a pupal case, before emerging as adult flies to start the cycle over again.

How Much Damage Do Cabbage Maggots Do?

The feeding damage to the plant’s roots can cause the plant to become stunted, yellow, and wilted. The larvae can also girdle the roots, causing the plant to die. The feeding damage can also make the plant susceptible to disease and other pests.

In severe infestations, the damage caused by cabbage maggots can result in complete crop failure.

10 Methods to Prevent and Get Rid of Cabbage Maggots

It is important to monitor for the presence of cabbage maggots and implement control measures when necessary to reduce the damage they cause to crops and support the health of your garden.

1. Use row covers: Covering seedlings with row covers can help to prevent adult flies from laying their eggs near the base of the plant.
2. Plant transplants through slits in barriers: Install barriers around your garden, such as fine mesh or floating row covers. The barriers should be tall enough to completely cover the plants, and they should be anchored to the ground to prevent the flies from accessing the plants. Make slits large enough to accommodate the transplant pots. Plant your transplants through the slits in the barriers, and cover the roots completely with soil. Close the slits, ensuring they are completely sealed to prevent the flies from accessing the plants.
3. Uprooting and burying or destroying the roots of crops after harvesting the tops: After the tops of your crops have been harvested, the roots should be removed from the soil. Uproot the roots, removing as much of the root system as possible. Bury the roots deep in the soil or destroy them by burning or composting them. This will help to prevent the pupae from emerging as adult flies, reducing the populations of Delia radicum in your garden.
4. Purchase parasitic nematodes: Apply the nematodes to the soil around your crops, following the label instructions carefully. The nematodes will infect the larvae of Delia radicum, killing them and reducing the populations of the pest. Maintain soil moisture, as the nematodes require a moist environment to be effective. Repeat applications of parasitic nematodes every 2-3 weeks, as needed, to maintain their populations and effectiveness.
5. Wood Ashes: Sprinkle a thin layer of wood ashes around the base of your crops. The sharp edges of the wood ashes can deter the flies from laying their eggs near the base of the plant.
6. Diatomaceous Earth: Sprinkle a thin layer of diatomaceous earth around the base of your crops. The diatomaceous earth will desiccate the larvae of Delia radicum, killing them and reducing the populations of the pest.
7. Hot Pepper: Mix hot pepper with water to make a spray and apply it to your crops. The hot pepper will deter the flies from laying their eggs near the base of the plant.
8. Companion planting: Choose companion plants that repel Delia radicum, such as garlic, marigolds, radishes, sage, tansy, thyme, or wormwood.
9. Practice crop rotation: Planting crops in different areas of your garden each year can help to reduce the populations of Delia radicum, as they will have a harder time finding and infesting the new crops.
10. Apply insecticides: In severe infestations, insecticides can be used to control Delia radicum populations. However, it is important to choose insecticides that are safe for beneficial insects and the environment and to follow the label instructions carefully.