Few "bugs" bug people more than flies. It's no surprise. There are at least 16,000 species of true flies in North America, along with countless fly look-alikes (defined colloquially as any insect with wings). And, just one pair of flies can produce as many as 1 million offspring over a 6- to 8-week period.
Mosquitoes, midges and gnats are examples of true flies. Many other insects carry the name “fly,” though they’re not true flies. One easy (but not foolproof) way to tell the difference is that the names of true flies, such as fruit flies, house flies, and crane flies are two words. Non-fly flies, including butterflies, fireflies, sawflies and mayflies, are one word.
Flies do play a useful role, acting as nature's vacuum cleaners and speeding up the demise of decaying matter. Flies also help pollinate some plants. But many are bad news, especially for gardeners.
Black flies can swarm heavily in humid summers. House flies, along with mosquitoes, might carry any of 100 diseases such as typhoid, cholera and malaria. House flies feed on rotting garbage and animal feces, and then land on objects that people touch or eat. Biting flies, such as horse flies and sand flies, are as painful as they are annoying. Whiteflies are among America’s leading crop- and greenhouse-destroying pests. Fungus gnats attack many a houseplant.
Sanitation is the leading strategy to cut down fly populations. Clean up spills immediately and thoroughly, and cover food when cooking out and picnicking. Dump any standing water, including buckets, trash or even birdbaths to discourage water-breeding. Cover rain barrels to prevent mosquito breeding. Take note of puddle-prone areas in the landscape, and consider laying pavers if the fly problem worsens.
Netting and sticky traps are non-chemical ways to handle pesky flies. Turn to repellents and insecticides if the problem is really out of hand. Always read the label carefully and completely for safety.