Apple Maggots

Identification

Size: The adult flies are about a quarter of an inch (6-7 mm) long

Color: Adult apple maggot flies have a distinctive appearance: their bodies are black with white bands

Description: Apple maggots (Rhagoletis pomonella) are pests that are particularly problematic for apple growers. The adult flies are about a quarter of an inch long, black with white bands, and have distinctive banded wings. They lay their eggs in apples, and the larvae, or maggots, then feed on the apple from the inside, causing significant damage. The larvae are creamy white in colour, legless, and measure about 1/4 to 1/3 of an inch in length when fully grown. They typically have a pointed head, and a cylindrical body, and are responsible for the major harm to apple crops.

Apple maggots (Rhagoletis pomonella), also known as railroad worms, are small insects that are considered significant pests for apple crops. They are native to North America and are most commonly found in the northeastern United States and eastern Canada, although they have gradually spread to other regions including the northwestern U.S.

The adult flies are about a quarter of an inch long and have a distinctive appearance with black and white banded bodies and wings. They lay their eggs inside apples, and once these eggs hatch, the larvae (or maggots) feed on the fruit, causing considerable damage.

While their primary host is the apple tree, apple maggots have been known to infest other fruit trees as well, such as hawthorn and cherries. Their life cycle is closely tied to the availability of their host fruit, meaning they’re most active during the apple-growing season. It’s important to note that while they are a serious pest for commercial apple growers, apple maggots do not harm humans or pets.

Identifying apple maggots involves observing both the insect itself and the signs of its presence:

Adult Appearance: Adult apple maggots are small flies about a quarter of an inch long. They have distinctive black and white banded bodies and wings, giving them a somewhat wasp-like appearance.
Larvae Appearance: The larvae, or maggots, are creamy white, legless, and about 1/4 to 1/3 of an inch long when fully grown. They have a pointed head and a cylindrical body.
Egg-laying Dimples: Adult female flies lay eggs just under the skin of the apple, creating tiny dimples on the apple surface that are visible to the naked eye.
Damage to Apples: As the maggots grow, they eat the apple from the inside, creating winding, brown trails throughout the fruit. Infected fruit often falls prematurely from the tree.
Host Trees: Apple maggots primarily infest apple trees, but they can also affect other fruit trees, such as hawthorn and cherry trees. If these trees are showing signs of infection, apple maggots could be the cause.

Regularly inspecting your apple trees for these signs, especially during the apple-growing season, can help with early identification and control of apple maggots. If you suspect an infestation, consider reaching out to a local extension service or pest control professional for advice.

Apple maggots can cause significant damage to apple crops. Here are some signs that may indicate you have an apple maggot infestation:

Dimpled or Discolored Apples: One of the earliest signs of apple maggot infestation is the presence of small, dimpled spots on the surface of the apples. These are the places where the adult female has laid her eggs. As the maggots grow and feed, they leave brown trails inside the fruit, which can cause discoloration or a blemished appearance.
Prematurely Falling Apples: If apples are dropping from your trees earlier than normal and show signs of internal damage when cut open, it may be due to apple maggots.
Presence of Flies: Adult apple maggots are flies that are black with white bands and have a distinct “F” shaped banding on their wings. If you see these flies around your apple trees, especially during the summer months, they might be laying eggs.
Brown Trails in Apples: Cut open an apple that has fallen from the tree. If it has brown trails, this could be an indication of apple maggots. These trails are left as the maggot eats its way through the apple.
Affected Other Fruits: Apple maggots can also affect other fruits like hawthorns and cherries. Check these fruits for similar signs of infestation.

If you notice these signs and suspect you have an apple maggot problem, consider reaching out to a local agricultural extension service or a pest control professional for advice on managing the infestation.

To prevent apple maggots and protect your apple crops, you can employ several preventive measures and control strategies. Here are some effective methods:

Clean orchard management: Practicing good orchard sanitation is crucial in controlling apple maggots. Remove fallen or damaged apples from the ground and destroy them. The maggots overwinter in fallen fruit, so removing and destroying them helps break the life cycle.
Timely harvest: Harvest apples as soon as they are ripe. Promptly pick up any fallen apples to prevent the maggots from entering the ground to pupate.
Fruit bagging: Covering individual apples with fine-mesh bags or nylon footies can prevent apple maggot flies from laying eggs on the fruit. Bagging should be done early in the season when the flies start appearing and should be continued until harvest.
Trapping: Place sticky red sphere traps in your apple trees to monitor the presence and activity of apple maggot flies. The flies are attracted to the red color and get stuck on the traps, reducing their population.
Insecticide application: If apple maggot populations are high and other preventive measures are not sufficient, you may need to use insecticides. Consult with local agricultural extension services or experts to choose the appropriate insecticide and apply it according to the recommended schedule.
Surround kaolin clay: Surround is a type of kaolin clay spray that forms a physical barrier on the apple surface, making it less attractive to apple maggot flies. Apply Surround early in the season to provide protection and deter the flies from laying eggs.
Biological control: Some natural predators and parasitic wasps feed on apple maggots and can help control their population. Research and consider introducing beneficial insects or nematodes to your orchard.
Crop rotation: Rotate your apple trees with other non-host plants to disrupt the apple maggot life cycle. This reduces the chances of infestation and helps in managing the pest over the long term.

Remember to combine multiple prevention methods for effective control. Integrated Pest Management (IPM) techniques, which involve a combination of preventive measures, biological controls, and targeted pesticide use, can help manage apple maggots while minimizing environmental impact. It’s also important to stay informed about local pest management recommendations specific to your region.