Carrot Rust Fly: How to Identify, Prevent and Get Rid of Carrot Rust Flies

Carrot rust fly, carrot root fly, or Psila rosae is a significant pest to carrots and other related crops within the same family. They can result in aesthetic damage and in severe instances, will lead to profit loss amongst commercial growers. To prevent such problems and frustrations, it is important to be aware of how to get rid of carrot rust fly.

The adult lays its eggs in the soil next to its host plant. Upon hatching, it turns into a larva, which is yellowish-white in color. They are legless and can reach a maximum length of 1/3 inch. This is the most destructive stage of the pest, which is why it is best to destroy the eggs even before they hatch. Once the larva reaches adulthood, they become flies with greenish-black body. The average length is 1/5 inch. They have yellow hair, head, and legs. They are fast flyers, and hence, it will be challenging to catch even if you spot them.

Carrot Root Fly Larva

Carrot Root Fly Larvae is the Most Destructive Stage of The Pest

Carrot Rust Fly’s Habitat

The eggs will be laid on the soil around May to June. It will take only ten days for the eggs to hatch. The larvae, meanwhile, will tunnel on the soil and from here, they will find their way to the roots of their host plant. This is also the stage when they result in the worst damage. They will first feed on the root hair before completely penetrating their host crop. Within three to four weeks, they will undergo pupation under the soil. By August, they will turn into adults and at this point, they are already harmless.

Identifying Carrot Rust Fly’s Damage

Plants Affected

Obviously, the main host plant for this pest is carrot. It also affects other plants, such as celery, dill, parsnip, fennel, and caraway, among others. These crops have a distinct odor, which attracts female near them, making it lay their eggs during the season.


The following are some of the most common visual cues that will give you an idea of the presence of carrot rust fly:

  • Because they chew roots, the latter will show most of the signs of the damage. When the crops are under the soil, it is impossible to tell the extent of the damage. Upon harvest, however, you will see entry holes and tunnels, which will be reflective of the feeding of carrot rust fly.
  • Soft-rot will also be most likely evident. This is a bacterial disease wherein the stored crop will have watery spots and develop an offensive smell.
  • Pay attention to the appearance of the root crop as well. In the case of carrots, for instance, the presence of carrot rust fly may make it develop a fat and bulging appearance, which is unattractive.

Results of Infestation

While it is seldom that the host plants are killed, it is common for them to suffer from stunting. They do not reach full maturity because of the tunneling in their roots. This affects the size of the resulting crop and may make it unmarketable. In the end, commercial growers may suffer the most as it can equate to a significant loss in profit. There will be deformity in the roots, making it create cosmetic damages. This also makes it prone to the entry of other organisms that can bring a variety of plant diseases. Even after harvesting, the larvae of carrot rust fly can still survive in the stored roots, which makes it critical to continue monitoring for the presence of this pest.

Damaged Carrot

Carrots Damaged by Carrot Rust Fly

How to Get Rid of Carrot Rust Fly

Natural and Organic Solutions

The following are some of the best ways to control and eliminate carrot root flies in a manner that is safe and effective:

  • Clean the garden often. Carrot rust flies can survive in vegetative debris. This will be a breeding ground and overwintering site for the larvae. Destroy any possible area that they will find suitable for survival.
  • If you are into organic farming, the good news is that there are insecticides that you can use without worrying about toxicity. Those that contain neem oil, spinosad, and natural pyrethrum are some of the best. They are effective in killing only the pest and not other insects or mammals.
  • Biological control will prove to be effective. Encouraging the presence of beneficial insects and birds in the plantation or garden will work, although you can also buy and release them. Chicken and birds will help as they can feed on the larvae and prevent them from wreaking havoc. Reduction of their population will also be possible with the help of beneficial nematodes.
  • Another natural solution that you might want to try is the use of rock phosphate, which you need to sprinkle on the top of the host plant. After raining, be sure to sprinkle again. It is common as a fertilizer for encouraging the healthy growth of plants, but it is also a natural way to eliminate common pests.
  • Using sticky traps will also be a good idea. However, keep in mind that this will be more of a trick to monitor their presence. If it traps a lot of carrot rust flies, this is an indication of the severity of the damage and the immediacy of the action that is required to control the infestation.

Chemical Solutions

Many commercial growers may resort to chemical control, but this is not actually a wise decision. Many of these chemicals can be toxic to other insects. They can also have a negative effect on the quality of the crops, especially with improper application. Nonetheless, if you would want to resort to the use of chemical controls, look for those that contain carbofuran and chlorfenvinphos. These are active ingredients that you can apply at seed furrow for controlling the population of carrot rust flies. Furadan, Yaltox, and Birlane are some of the popular brand names of pesticides that contain these ingredients.

How to Prevent Carrot Rust Fly

Protecting the crop from carrot rust root fly will make it less susceptible to serious infestation. With this, one of the best things to do is to use floating row cover, which will provide a protective barrier above the plant. However, be sure to remove the covers after the seedlings emerge.

As an alternative to floating row covers, you can also sue vertical fencing or window screens. This will prevent flying adults from getting in contact with the plant and laying their eggs on the soil.

It is also important to keep the surroundings clean. During the winter, any decaying crop or vegetation can provide carrot rust flies with a suitable habitat for overwintering.

Also, it will be good to consider growing plants that resist carrot rust fly. Among others, flyaway carrot is one of the best.

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