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Maggots Turning Into Flies — Everything You Should Know

Rowan Burgess |

The rate at which maggots turn into flies is rapid. When you’ve got an infestation, you need to act immediately.

Here, we cover everything you need to know about maggots turning into flies. Armed with this knowledge, you can figure out what’s attracting them to your farm and get rid of them once and for all. Read on to find the most effective solution for maggot control and prevention on farms. 

How Maggots Turn Into Flies

A fly can develop from egg to adult form in less than a week. Knowing what stage your infestation is in can help you figure out the most effective pest control solution. 


The egg begins the lifecycle of a fly. You’ll know a fly egg based on its appearance; it’ll look like a grain of rice. The eggs will hatch from 8-20 hours after the adult fly has laid them.

Larvae Stage

The First-Instar Phase

The freshly emerged maggots typically measure 0.079 inches long. They begin feeding by consuming fluids from the meal left to them. As they feed, they travel further into the meal.

The Second-Instar Phase

Depending on their surroundings, the typical first-instar maggots will moult into their second-instar phase within 24 hours. Here, they reach 0.2 inches long. As with the first-instar maggot, the larvae move around its feed for another 24 hours before growing to 0.4 inches long. At this stage, it’ll moult again to enter the third-instar phase. 

The Third-Instar Phase

The larva is more prominent during this stage. The larvae feed and migrate further into their meal, usually in a mass of maggots.

During the third-instar phase, the larvae will grow to 0.6-0.79 inches long just before they enter the pre-pupa phase of their growth. 

The Pre-Pupa Phase

At this point, the larvae cease feeding. They move away from their food source to discover a space for pupation, such as beneath the soil. It takes approximately four days to go from the pre-pupa stage to the pupa stage.

Pupa Stage

Like butterflies, flies are holometabolous insects; they experience a complete metamorphosis from larvae into adults. Metamorphosis occurs in the pupation stage, where their previous form degenerates.

Scientists have noted many reasons why metamorphosis occurs in the later stages of development, including increased development speed. As an air bubble leaves the pupa, it fills its puparium (a shell similar to a butterfly’s cocoon) to create space for what will become a fly’s legs, head, and wings. 

These features develop and fully form in the puparium. This stage lasts approximately ten days before the puparium reaches the adult fly. 

Adult Fly

Once the pupa phase is over, the maggot is an adult fly, and the phases return to the beginning, and the cycle repeats.

A female fly will be ready within two days to reproduce and only stays pregnant for 24 hours before being able to hatch her eggs, illustrating just how quickly a fly infestation can occur. The adult fly will lay eggs in typically warm, moist environments with a food source that maggots can easily feed. Usually, though not always, flies will lay eggs on decaying objects or corpses as it’ll provide days' worth of food. 

What Attracts Maggots and Flies?

Many factors will entice flies into your home or workplace. Maggots and flies thrive in specific environments and can reproduce rapidly if not noticed.

  • Waste—Rubbish is an excellent food source for larvae, so when flies are looking to lay eggs, it’s no surprise they lay them in amongst fermenting fruit, old meat, decaying fruit, and rotten vegetables. Keep your bin lids firmly closed to ensure that flies don’t lay eggs inside and to avoid a swarm of unwanted pests lingering around it.
  • Faeces—Almost all flies feed off faeces. Flies often carry harmful bacteria and transmittable diseases as a result. 
  • Carcasses—Flies linger around carcasses because they’re an excellent food source for their offspring. They often lay their eggs on a carcass so their larvae have good feed when they hatch.
  • Warm areas—Flies will gravitate to warm temperatures because they’re optimal for laying eggs. However, in winter, the fly can adapt to survive the temperature change, still able to lay eggs ready to hatch come spring. 
  • Liquids—Any spilt liquid will attract flies for hydration and consumption. 
  • Light sources—A positive phototaxis process, where a living organism gravitates towards the light, will occur when flies see almost any light source. 
  • Other flies and insects—The presence of other insects attracts flies. It’s also promising for mating and reproducing, so flies will gravitate towards other flies of its kind. 
  • Plants—Flies are attracted to certain plants, including daisies and sunflowers, for feed. Flies not only lay their eggs on these plants, but they also drink from them.  These plants often act as a spot for flies to rest. 
  • Unattended food—Flies aren’t particular about what they eat. Whether fresh food or decaying, flies aren’t picky. Piles of compost or rotting fruits and vegetables are particularly attractive.

Maggot Control and Prevention On Farms

Farms often have multiple sources that attract flies, from animal faeces to overripe fruits and vegetables. Even items like animal feed can be appealing to flies.

It’s hard to get rid of flies once they arrive. While the current decline of insect diversity is a concern more generally, a fly infestation could cause serious harm to your business and create an increasingly unhygienic space for you, your livestock, and anyone working on your farm. 

Besides keeping your farm as clean and tidy as possible, it’s best to use ​​Maggots Grandular Larvicide. The solution will prevent and control the fly problem in the earliest stages of development.

Frequently Asked Questions

How Long Does It Take for a Maggot To Turn Into a Fly? 

Under optimal conditions, going from egg to adult fly can occur in under seven days.

Can Maggots Turn Into Flies Without Food? 

Maggots will typically only last 2-3 days without any food source. 

Final Thoughts

A larva can turn into an adult fly quickly. The fast reproduction rate means you must work quickly to eliminate these pests from your farm. Don’t wait to get any problems under control—act now and check out Dalton Engineering for insect control solutions!