Ticks, Mosquitoes, and Biting Flies! Oh My!

Spring is my favorite time of year in Minnesota. The trails are green, the waterfalls and rivers are rushing, and the temperatures are perfect for hiking. Plus there is the promise of several months without snow! But with the nice weather come a variety of bugs that are not as nice.

By mid-May, at my day job (I work as a veterinarian) I have already pulled several ticks off of multiple dogs and have answered more than a couple queries about dogs with “bullseye” lesions on the dogs’ abdomens (typically caused by biting flies). And although I don’t typically get calls about mosquitoes, we know that they are emerging and ready to spread heartworm disease.

All three of these bugs (ticks, mosquitoes, and biting flies) are a nuisance to both people and dogs. And some can even pass along life-threatening diseases. So it is important to have a good plan to keep your dog protected from all three while out exploring the great outdoors.

In this blog post, we will briefly discuss why it is important to protect your dog against ticks, mosquitoes, and biting flies. And then we will discuss solutions to the bug problem.

Today’s beautiful spring walk near our home in Minnesota. The bugs weren’t too bad today, but I pulled a dead tick off of Glia last week, so we know that ticks are out.

Here’s a quick table of contents for this article so that you can skip right to the part you are most interested in:

  • The Bugs
    • Ticks
    • Mosquitoes
    • Biting Flies
  • The Solutions
    • Monthly Preventatives
    • Permethrin Coated/Repellent Dog Gear
    • Sprays and Wipes

The Bugs


Ticks can be found throughout the United States. And they carry a variety of diseases with them. Here in Minnesota, the two main tick-borne diseases seen in dogs are Lyme disease and anaplasmosis. Ticks transmit these diseases when they attach to dogs (or humans) and take a blood meal. Ticks have to be attached for over 24 hours to transmit Lyme disease, but anaplasma can be transmitted faster.

In addition to spreading disease, ticks can leave irritation at the site of the tick bite. And dogs can even suffer from a tick-bite paralysis if they have too high of tick burden.

All of these are reasons to work hard at reducing your dog’s exposure to ticks.

If you are interested in more details about ticks and dogs, check out our blog post devoted solely to this topic.


Ever heard about that other Minnesota state bird? Yep, that would be the large mosquito. Mosquitoes are also found around the United States, but here in Minnesota, we find that they love summer along our lakes and swampy trails.

Just like in people, mosquitoes can cause small red bumps and mild allergic reactions when they feed on dogs. And they are definitely a nuisance buzzing around your dog’s face. But even more importantly, mosquitoes spread heartworm disease.

Heartworm disease is just what it sounds like… worms, living in your dog’s heart. These worms can cause plenty of damage to your dog’s heart and blood vessels. And treatment is expensive, long, and requires months of exercise restriction for your pup. So prevention is definitely better than treatment of heartworm disease.

Want to learn more about heartworm disease in dogs? You can find everything you need to know about heartworm disease in cats and dogs at HeartwormSociety.org.

Biting Flies

Our third featured bug is the black fly. Biting black flies are mostly harmless, but they can cause alarming red spots on a dog’s belly. And as anyone who has been bitten by a fly can attest, fly bites hurt. Not to mention flies are potentially more annoying than mosquitoes as they buzz around your head.

I know they certainly irritate my dog, Glia. She will leap up and try to bit at them. And Glia must not be alone in this response, as the term “fly-biting” is used to describe a type of partial seizure sometimes seen in dogs.

For those of you who haven’t seen black fly bites on a dog before, the image below is a classic example. The fly bites tend to appear on the thinly furred part of the dog’s abdomen and inner thighs and are bright red solid or bullseye rashes about the size of a nickel.

The Solutions

There is no one perfect solution that will keep your dog fully protected from ticks, mosquitoes, and biting flies. But by using a combination of the approaches below, your dog can significantly reduce his or her exposure to these insects.

Monthly Preventatives

There are many different monthly preventatives aimed at killing fleas and ticks. And there are others that prevent the development of heartworm disease.

The only preventatives that protect against all three are the oral chewable Simparica Trio (released this year) and possibly Vectra 3D. However, Vectra 3D does not kill mosquito larvae, like a classic heartworm preventative, so most veterinarians do not consider this a replacement for traditional heartworm preventatives.

Flea/Tick Preventatives

For flea/tick prevention, there are topical, oral/chewable, or collar options. We discuss these options in more detail in our post about surviving tick season with your dog.

I personally use a chewable, called Nexgard, monthly in both of my dogs, When heading out backpacking or camping in a highly tick populated area, I will occasionally double up with a topical, like Frontline.

Why not just stick with the oral chewable? Well, the problem with a chewable is that a tick has to bite the dog in order to take a blood meal before they are killed. The chewables work great, killing the ticks before the 24 hour period needed to transmit Lyme disease. In fact, I often find dead ticks in the pups’ beds after a tick-infested hike.

However, I don’t really like the idea of carrying the ticks into the house with the dog after a hike. And I especially don’t like sharing a tent with ticks that haven’t attached to my dog yet. It is so easy for the tick to crawl off of the dog and onto me.

You may then also wonder why I don’t just use a topical or collar instead of the chewable. Personally, I don’t like the oil on my dog’s backs (plus Glia always tries to rub hers off on the carpet, so I have to walk the dogs right after applying a topical). And I typically remove collars at night. The flea/tick collars, like Seresto, need to stay on 24/7 to be the most effective.

Heartworm Preventatives

For heartworm disease prevention, I personally use a monthly Heartgard chew in my dogs. It is important to note that heartworm preventatives typically work retroactively by killing any heartworm larvae that a mosquito would have deposited in the dog over the past month. Generally, heartworm preventatives do not kill or repel mosquitoes.

The one exception to this is Vectra 3D, which is labeled to repel and kill mosquitoes. According to the official website, 80% of mosquitoes will avoid landing on dogs treated with Vectra 3D.

You can talk to your vet about the right combination of monthly preventatives for your dog, but for most dogs, I highly recommend some form of monthly preventative before heading out onto tick and mosquito infested trails.

Biting Fly Protection

If black flies are a big concern for you, Vectra is the only preventative that I am aware of that also has a label to claim that the product repels and kills biting flies.

Honestly, we haven’t tried Vectra 3D yet, but we are definitely considering it as an option to help keep mosquitoes and flies away from Glia during our backpacking adventures this summer.

Keeping biting insects away from GLia is especially important to me, as she has had allergic reactions from bites before. Part of the reason we carry Benedryl in our first aid kit is that Glia will get a swollen face if she receives too many mosquito bites.

If you are interested in learning more about Vectra 3D, here is an overview video made by the company who produces this preventative.

And please remember to talk with your veterinarian before switching preventatives. Some products may not be recommended for use for your dog. And many of these products require prescriptions from your veterinarian before you can purchase them.

Repellent Dog Gear

Human hikers often use permethrin treated products to protect themselves against ticks and other insects on the trail. Did you know that this is an option for dogs as well?

Permethrin is the only pesticide approved by the EPA for these uses. When it is applied properly, permethrin binds tightly to the fabrics, resulting in little loss during washing and minimal transfer to the skin. Permethrin is poorly absorbed through the skin, although sunscreens and other products may increase the rate of skin absorption.

National Pesticide Information Center

You can purchase permthrin treated products for your dog, or you can treat gear your dog already has. Just be cautious if you have a cat in the house. Permethrins are toxic to cats!

Pre-treated Dog Gear

If you are looking for treated gear to purchase, consider the Hurrta Sun and Bug Blocker. This product uses a fabric technology called Archroma Santized finishing. Textiles with a Archroma Sanitized finish offer permithrin-based durable and safe protection for dogs.

The fabric finish is supposed to retain efficiency even after 100 washes and claims to keep mosquitoes, ticks, and horseflies from landing. The treatment is dermatologically tested and safe to use on dogs, although there is a disclaimer that it may cause a reaction on sensitive skin.

This is an Amazon link. As an Amazon Associate, I earn from qualifying purchases.

Glia and I have not tried the Sun and Bug Blocker yet, but the fit appears similar to the Hurrta Body Warmer, which we have tried. You can find our review post of the Body Warmer here. Or if you are looking for a good review on the Sun and Bug Blocker itself, check out HikingGirlwithDog.com’s review.

On a tighter budget? Consider these options from Insect Shield. Insect Shield is a company that originally started designing permethrin-treated clothing for people. In fact, the company is the first to have EPA registered insect repellent apparel. And now they also have some products for our canine companions.

The Insect Shield process binds a permethrin formula tightly to fabric fibers. Per the company’s website, this results in effective, odorless protection that lasts the expected lifetime of apparel (or at least through 70 launderings). Insect Shield® Repellent Gear has been proven and registered to repel mosquitoes, ticks, fleas, and flies.

Here are a few links to Amazon for some of Insect Shield’s dog gear products.

Treating Products with Permethrin at Home

If you prefer to treat the products you already have at home, there are several good guides you can find online. But the best instructions to follow are the instructions that come with the type of permethrin that you purchase.

You should use a permethrin product that is intended to be used on clothing/fabric. Treat your dog’s gear ahead of time and preferably outside, but at least in a well-ventilated area. Make sure the product is dry before your dog wears any of their treated gear.

ConsumerReports.org has a thorough article all about using permethrin treatments on clothing. Most of the information is applicable to treating your dog’s gear also.

Insect Sprays and Wipes

There are many different sprays and wipes, whether repellents or pesticides, that are on the market today. And while I have sprayed my dog’s gear with DEET before, DEET can be irritating to dogs and definitely should not be ingested by them. So what are some more pet-friendly options? The two that I find recommended the most are Wondercide and Vet’s Best.

Wondercide Sprays and Wipes

Wondercide produces a range of products to help protect pets from fleas and ticks. The products are both a preventative and a treatment, in that they have been formulated to kill and repel ticks, fleas, and mosquitoes. The company creates the sprays and wipes from food-grade ingredients in the USA. No artificial colors, fragrances, or synthetic pesticides are reported to be used in Wondercide products.

The sprays and wipes can be reapplied as frequently as needed. My dogs aren’t a huge fan of sprays, so we are planning on trying Wondercide’s wipes during our summer hiking season this year.

Here’s a YouTube video from Wondercide about their flea and tick wipes.

Vet’s Best Products

Vet’s Best also uses plant-based ingredients, including lemongrass oil and geraniol (from citronella plants). Like Wondercide, this company has sprays to apply to dogs as well as sprays to treat the home and yard.

Here is a video from Vet’s Best for comparison to the Wondercide information above.

Keeping Your Dog Safe from Ticks, Mosquitoes, and Biting Flies

Ultimately, keeping your dog safe from the variety of bugs in the great outdoors may require a combination of products. I highly recommend that every dog is on some sort of monthly preventative. Talk with your vet to pick the best one.

I have personally used Advantix, Frontline, Simparica, Credelio, and Nexgard with my dogs. We are currently on Nexgard, mostly due to the convenience of an oral chew versus a topical. But we have not had problems or reactions with any of the products that we have tried.

Additionally, I have hiked with dogs using a Seresto collar and was impressed with how many fewer ticks were crawling on him compared to my own dog who was just on Nexgard at that time. (Remember, Nexgard has no repellent properties, but it does a great job of killing ticks who do end up biting).

This summer, we plan to try some permethrin-treated dog gear and get some wipes formulated for dogs. I have used natural product mosquito repellent wipes made for humans on my dogs in the past, but I will feel safer using a product like Wondercide, which is formulated with dogs in mind. I am hoping the Wondercide wipes work just as well as the wipes we have used previously.

Hopefully, this overview of available options for dogs will be helpful to those of you who are gearing up to starting hiking in heavy tick, mosquito, or fly areas.

And if you have any personal recommendations, let us know what works best to keep you and your dog safe from insects in the comments section below.

Happy Hiking!

Kate and Glia


Kate is the writer of Pawsitively Intrepid. She has spent the last 9 years working full-time as a veterinarian, treating dogs and cats. But as of June 2023, she is taking a year to travel with her dog, volunteer, and work on some passion projects.

Leave a Reply

Your email address will not be published. Required fields are marked *

Recent Posts