Maggots are the larvae of flies. While adult flies can attack plants and disrupt garden produce production, their larvae can be equally destructive. Maggots may eat away at the actual plant, bore into fruits and vegetables, and destroy plant roots. Though there are thousands of types of maggots, several types of maggots are common pests in North American gardens and fields.
Apple maggots (Rhagoletis pomonella), sometimes called railroad worms, are a major problem in apple orchards and backyard apple tree groves. The pests typically appear in midsummer. The adult flies lay eggs on the apple fruit, which hatch and produce maggots that bore through the apple. This often causes the entire fruit to turn brown and rot on the tree. After the apple falls off the tree, the maggots reach full size and mature into flying insects.
The blueberry maggot (Rhagoletis mendax) is a government-regulated pest common throughout the United States and Canada, with restrictions on blueberry product transportation and importation to help minimize the spread of this pest. This maggot is closely related to the apple maggot, but the two target their respective fruit exclusively. Flies lay eggs in the skin of ripe blueberry fruit, which hatch and result in tiny white maggots. The maggots feed on the blueberry, turning it into a liquid mush. This type of maggot may also attack other types of berries, including huckleberries and cranberries.
The cabbage maggot (Hylemya brassicae) attacks the seedlings of cabbages and broccoli plants and causes widespread plant destruction and death. The maggots bore through the underground parts of the plant, including stems and roots. The plant typically begins rotting within a week as its underground sections decompose from the maggot infestation. The maggots may also attack underground root crops such as turnips.
Seed Corn Maggot
Despite its name, the seed corn maggot (Delia platura) doesn't just target seed corn, but also some types of peas, beans and cabbage. The maggots typically emerge in the spring growing season. The flies lay eggs in the soil; they lie dormant over the winter and hatch as soon as the weather warms.