Black flies and ticks in Michigan

Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.

Anyone who has waded in a trout stream in northern Michigan during the early summer knows that black flies are among the worst biting flies that nature has to offer. They attack in large swarms and favor the face and around the ears for feeding sites. They get tangled in our hair and they get into our eyes. We breathe them into our noses and mouths. Their bites swell up, bleed and itch for weeks.

Michigan is blessed with over 65 species of black flies with the majority of species occurring in the northern areas where clean rivers and streams are numerous. All black fly larvae are aquatic and only develop in clean well-oxygenated moving water. It shouldn’t be surprising that one result of improving water quality in southern Michigan rivers and streams is a noticeable increase in the number of black flies.

Black flies are small, stout flies with a humpbacked appearance. Many that have fed on me have white stripes on their legs. Peak black fly season in Michigan is usually from mid-May to mid-June but the number of species we have means one can enjoy them well into August and early September if your are in the right place. The adult flies live for about two to three weeks. Only females bite. Males thankfully feed on nectar. Unlike mosquitoes, they do not come indoors, are only active during the day, and cannot bite through clothing.

You can protect yourself from black fly bites by wearing long-sleeved shirts and long pants. Tuck your pant legs into your socks and your shirt into your pants. Some say that the flies are attracted to dark colors so blue, purple, black, and brown may not be good fashion choices if you are in black fly country. Hats are a must and those equipped with netting may be the only way to keep them off your face and out of your hair. I have found that insect repellents containing DEET offer some protection but I have found that there are times the flies will bite regardless of the repellent or amount used.

As long as we’re talking about blood sucking parasites, let’s talk ticks. Tick season is just beginning to heat up. We received our first deer tick of the year last week from a veterinarian in Muskegon County who “collected” one from his dog patient. Deer ticks are the ticks that carry Lyme Disease and they are becoming more common in southwest Michigan north to Muskegon County. Unlike the American dog tick, deer ticks do not have white markings on their backs (see photos). We have several species of Ixodes ticks that look very much like the deer tick and some are quite common. If you remove a tick that does not have white markings, it might be a good idea to save the tick and have it identified.

Dog tick bites rarely result in serious disease in Michigan, but like other wood ticks, it is a known carrier of Rocky Mountain spotted fever and tularemia. The cases of Rocky Mountain Spotted Fever reported in Michigan have been from primarily southern counties, particularly those located directly north of the Toledo Airport. Also, toxins injected with their bites cause itching, fever and in some cases tick paralysis. People with recent tick bites should be on alert for any rash, which is a primary symptom of both Rocky Mountain Spotted Fever and tularemia.

Mice appear to be the preferred hosts of immature stages of the American dog tick and deer tick while the adults prefer to feed on dogs and other large mammals. Dog ticks can live for over a year without food. These ticks are most likely to be encountered in the spring and early summer along animal paths in grassy, shrubby areas adjacent to woodlots and forests. Family members and pets should be inspected daily where ticks are known to be abundant. Insect repellents containing DEET or permethrin applied to clothing will help keep wood ticks from biting. If an attached tick is found, it should be removed by placing tweezers near the head and gently pulling it off. Be careful not to squeeze the tick as this can inject the contents of the tick as well as possible toxins into the wound. Keep in mind that ticks cannot feed immediately after attaching. They require several hours to imbed their mouthparts deep enough to take a bloodmeal.

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