Flies

INTRODUCTION

The order Diptera includes flies, gnats and midges, but this article focuses primarily on flies. There are more than 100,000 species of flies worldwide and about 20,000 species within the United States.

WHAT DO FLIES LOOK LIKE?

Most species of adult flies have only one pair of functional wings, large eyes and their mouthparts are described as being sponging/lapping or piercing/sucking since many flies feed on blood.

The mouthparts of flies vary a great deal when it comes to their mandibles, structures that closely relate to teeth. Most adult flies suck up their food. Some flies have very large, sharp mandibles they use to cut the skin of a host that causes bleeding and then use other mouthparts to lap up blood. Other flies use a mouthpart that is needle-like and enables them to pierce the skin of a host and suck up the blood. Still other flies will liquefy solid food or else consume liquids by “sponging up” these foods and swallowing them.

Adult flies have three body segments (head, thorax and abdomen) and six legs and are either dull or brightly colored.

WHAT ARE FLIES ATTRACTED TO AND WHAT DO THEY EAT?

Generally, flies are attracted to filth such as garbage, feces, dead animals, decaying vegetation, produce and warm-blooded mammals. There are many species of flies that consume blood and the flesh of animals.

Adult flies consume only liquids since they do not possess the chewing mouthparts that are commonly found on insects that damage plants. Common sources of foods for adults are nectar, plant sap, blood, liquefied sugars and other sources of carbohydrates. Also, many species of adult flies do not feed at all.

HOW DO FLIES GET IN THE HOUSE OR BUILDING?

Flies get inside structures by flying through open doors and windows and hitchhiking inside on items brought into the home or building. One of the more common hitchhiking flies is the fruit fly. It frequently gets inside on infested fruits or vegetables. Flies also get inside when looking for places to overwinter, entering a building through cracks, gaps and crevices around the building’s windows, doors, soffit, facia boards and siding.

WHAT TIME OF YEAR ARE FLIES MOST ACTIVE?

Fly populations generally peak during the warmer months of the year. However, flies may also breed and develop year round in the hot, humid, tropical-like areas of the world. Also, flies that are overwintering inside may be seen when the winter temperatures warm up enough to stimulate fly activity.

SIGNS OF FLY ACTIVITY

The appearance of fly adults, pupae and larvae are the most likely signs of fly activity. Bites also indicate fly activity.

Some of the more frequently encountered flies around the home include house flies, fruit flies, blow flies, cluster flies, mosquitoes, fungus gnats and biting midges such as sand flies. Flies that often occur around animals are face flies, horse flies, screwworm flies, stable flies and deer flies. Interestingly, these flies will also bite humans and cause a great deal of annoyance and disease transmission.

FLY PREVENTION TIPS

In most cases, fly prevention involves effectively breaking up their life cycle, sanitation, reducing or minimizing the conditions that favor development and removing their sources of food. Therefore, some effective ways to help prevent flies are:

  • Clean up and remove fly food sources or what they are developing in, both inside and outside. In other words, practice sanitation measures.
  • As much as possible, place garbage into plastic bags and regularly clean containers and make sure to keep lids in place.
  • Don’t allow plant debris to pile up because flies will develop in or under the piles.
  • Both doors and windows should be screened and tightly secured. Of course, do not leave doors and windows open unless they are screened.
  • Eliminate dead animals around your property. Always follow safety guidelines when removing a carcass.
  • Keep gaps, holes and other potential fly entryways sealed, a measure that is especially important to help prevent overwintering flies from getting inside a structure.

TIPS TO HELP GET RID OF FLIES

While sanitation is the best long-term way to help control flies, in some situations using an approved insecticide aids greatly in helping to control flies. For example, flies could develop in a wall void where an animal has died and the only way to gain access to the source of the flies is to either remove the wall panels or use a directed application of insecticide. In addition, overwintering flies may become active and fly about, a problem that is especially alarming in schools and medical facilities.

When either of these situations arise, it is best to get your pest management professional (PMP) involved so you can minimize the impact of flies within the building. Your PMP may recommend the use of commercial fly control products, fly traps and fly baits to help reduce the fly population.