Flies, Gnats and Midges

Effective control of flies needs to include the larvae, since adults are highly mobile. Usually applying pesticides to fly breeding areas isn’t necessary, because cleaning up or eliminating the breeding area is more effective and longer lasting. But sometimes in areas such as dumpsters where total sanitation is impractical, various pesticides can be applied. If large numbers of flies are present, fogging can be done for an initial knockdown. Surface spraying windowsills, outside walls, or other outside resting areas can help eliminate some adults – but isn’t enough for total control. However, spraying outside walls deters cluster flies from getting into your home to hibernate, and is good defense in houses that get bad infestations.

Things you can do to help:

Sanitation is the best defense against most flies. Outside, taking extra steps to eliminate breeding areas will make a big difference. Garbage cans should be kept clean and tightly sealed, and garbage placed in plastic bags. This will cut down on attractive odors, and on sources of food for larvae and adults. Piles of rotting vegetable matter like hay can be harborage for some types of flies, and should be eliminated or covered. In addition, carefully disposing of animal carcasses around your property will keep many types of flesh-eating flies from completing their life cycle. Flies that are active at night are attracted to light. This means you don’t want regular bulbs or mercury vapor lights around areas inhabited by people at night. Replace these with yellow lights, or sodium vapor lights. Alternatively, you can use lights that attract them to lure them away from people, or a bug zapper light to kill adult flies. To keep flies from getting in your home, make sure your screens are well intact. Use size 10 screening for larger flies, and size 16 or 18 for mosquito-sized flies. If they do get in your house and you don’t want to use a flyswatter, various traps are available. Sticky traps, or mechanical traps are both effective. You can make a mechanical trap yourself relatively easy. Place an attractant in a jar (vinegar works good for fruit flies), and make a paper cone that fits down inside the jar. Flies will be able to easily get into the cone to get to the bait, but will have trouble getting out. If you have a garden and bringing in fruit flies with your harvest is a problem, try submersing your fruits and vegetables in a pail of water when you bring them inside. This should drown any hitchhikers, and keep new flies from getting into your crop until you get a chance to put it away. Cluster flies that get inside your house will be pretty lethargic, and can be vacuumed up if possible. If they are determined to be in a wall void, they are best left there until they emerge. Cluster flies killed and left inside voids can attract other, more nasty pests. For fungus gnats inside, first try and clear up the moisture which is causing the fungus. This could mean not watering your houseplants as often or fixing leaky plumbing. If this doesn’t work, various soil treatments (including nematodes) are available for killing the larvae in your plants. Sometimes gnats can be in voids or drainpipes. The plastic bag trick can be used here to find out their location. Tape a plastic bag over a drain hole, or for a wall hopefully you can remove an electrical cover (instead of cutting a hole) and attach the bag there. Gnats will go towards the light, and monitoring the bags will tell you if they are there or not. If they are found to be in a drainpipe, try to sterilize it by pouring boiling water down the drain.