By Charlie Pankey, Sierra Rec Magazine
There’s a reason backpackers sometimes refer to late June in the Sierra as “Mosquito Season.” There’s a special kind of serenity that comes with standing lakeside in the alpine hush—places like May Lake in Yosemite, Grass Lake in Desolation Wilderness, or Long Lake in the Hoover. But if you’ve ever lingered too long in the wrong season, you know that serenity can dissolve quickly into a desperate, slap-happy dance against swarms of mosquitos.
I’ll never forget one such evening at Fremont Lake in the Hoover Wilderness. After a beautiful loop past the PCT, our group arrived back at camp only to be greeted by a mosquito ambush so intense, we bailed. At 4 p.m., exhausted from a long day, we packed up and hiked two more miles just to escape. A similar scene unfolded at May Lake in Yosemite, where I tried to photograph the sunrise with my father. Within minutes, my hands and neck were under siege — the kind of relentless, precision bites that turn magic moments into rushed misery.
These are the kinds of backcountry experiences that make gear choices more than just comfort decisions. They can shape — or save — the adventure.
For years, adventurers have relied on chemically treated clothing and repellents to fight back. But in 2025, Royal Robbins is stepping into the mosquito protection game with a breakthrough that could reshape the way we approach bug season in the Sierra—without a drop of DEET or permethrin.
Enter MPT (Mosquito Protection Technology): a new, non-treated, tightly woven fabric developed in partnership with Vector Textiles, a company that’s quietly been leading a revolution in chemical-free, insect-resistant materials. Unlike other mosquito gear that uses coatings or pesticide treatments that degrade over time, MPT provides a 92% effective barrier built right into the fabric structure itself. There’s no spray to reapply, no treatment to wash out, and no trade-off between comfort and coverage.
But the story behind MPT goes beyond gear testing. It’s part of a larger movement—one rooted in sustainability, responsible travel, and minimizing our footprint in delicate alpine ecosystems. Royal Robbins’ commitment to chemical-free protection doesn’t just serve the user; it benefits the wild places we love. Mosquito-treated clothing with biocides can potentially leach into waterways or affect soil composition when laundered or discarded. MPT offers a clean alternative for conscientious outdoor travelers.
The company spent a full year field-testing the new fabric, putting it through real-world rigors in both hot and wet environments—the exact kind where mosquitos flourish. The verdict: the tight weave held strong, blocking the majority of mosquitoes and eliminating the need for topical chemicals.
The Future of Alpine Layers
It’s easy to overlook how much bugs influence our decisions in the backcountry. I’ve cut sunset fishing sessions short at Grass Lake and rushed breakfasts at May Lake just to escape the buzzing cloud. But if this technology continues to evolve—and if it delivers across seasons and elevations—we may be entering a new chapter in backcountry layering, where comfort, protection, and sustainability are finally in sync.
MPT isn’t magic. But it’s a massive step forward—especially for those of us who explore the Sierra’s most mosquito-prone places in mid-summer. And the best part? No toxic coatings, no chemical runoff, no compromise on comfort.
What’s Next
We’ll continue testing this new MPT line throughout the 2025 season — and we’re especially excited to bring it back to the very places that once chased us off with buzzing vengeance. Expect full reviews on specific pieces and field updates as summer unfolds across the Sierra.
But perhaps what makes this launch even more meaningful is where it comes from. Royal Robbins was born in Yosemite. The brand was built by climbers and explorers who shaped modern adventure culture in the Sierra — designing gear not just for function, but with a deep respect for the environment and the experience.
This latest innovation isn’t just smart gear — it’s a reflection of that same ethos: thoughtful, sustainable, and made for those who venture deep into the wild.
In a place as iconic and challenging as the Sierra Nevada, it’s fitting that a legacy brand from Yosemite is still leading the way.
