Gear

Insect repellent and head nets

A bottle of insect repellent and a rolled-up head net on a table.

DEET, picaridin or citrus, how long they last, and when a head net simply beats repellent. Also: the difference between mosquitoes, midges and ticks, and what permethrin does to clothing.

Mosquitoes are not a general problem in Norway — they are a local and seasonal one. On a basic course in Sørlandet in June you may get away with a jacket. On a bog in Indre Finnmark in the second half of July, nothing short of repellent and net combined will do. That decides what you bring.

Active ingredient — DEET, picaridin, citrus

Three active substances dominate the market. They differ in how long they last and how they feel on the skin.

DEET (N,N-diethyl-meta-toluamide) is the most tested and still the most effective. Concentration governs duration, not effect — 100% DEET stops no more mosquitoes than 30%, it just lasts longer. Rule of thumb:

  • 10% DEET — 2–3 hours
  • 20% DEET — 4–5 hours
  • 30% DEET — 5–6 hours
  • Above 30% gives little extra duration, and is rarely worth it.

DEET dissolves certain plastics and synthetics (watch glass, spectacle frames, Gore-Tex printing). Apply it to your hands before your watch, not after.

Picaridin (icaridin) is newer, about as effective as DEET at the same concentration, and does not attack plastic. 20% picaridin gives roughly 6–8 hours of protection. It smells less, with a greasier consistency. Preferred by those who find DEET unpleasant.

Citrus-based (PMD, oil of lemon eucalyptus) is the “natural” alternative. A real effect, but short-lived — typically 1–2 hours — and not recommended for children under three. Usable on an evening outing in mild mosquito season, not in Indre Finnmark.

Tablet-based and spray-based repellents are equally effective if they contain the same concentration. Spray covers more easily, tablets/roll-on leak less in the pack.

Mosquitoes, midges and ticks — three different problems

It is easy to lump them all together, but they behave differently and call for partly different measures.

Mosquitoes fly and bite — often at dusk and night, often near water and bog. Repellent and net work. Long sleeves help.

Midges are smaller, suck rather than bite, and come in swarms when it is still and warm. DEET works partly; a fine-mesh net (under 0.6 mm mesh opening) is often the only thing that actually keeps them out. An ordinary “mosquito net” has too large a mesh.

Ticks sit in grass and low scrub and attach themselves as you walk past. Repellent on the skin works weakly; permethrin on clothing works much better. Check your skin after the trip — ankle, behind the knees, groin, navel, scalp. A tick removed within 24 hours rarely transmits borrelia.

Permethrin — repellent on clothing, not skin

Permethrin is an insecticide that binds to clothing fibres and lasts six washes or longer. You spray or dip the clothes (not the skin) — typically trousers, socks, jacket. The insects land, take up a dose, and either die or fly on.

In Norway, ready-treated garments are sold by several manufacturers (Fjellreven Vidda Pro Ventilated, Bergans Senja, Helsport myggstopp). You can also buy concentrate (Sawyer Permethrin) and treat them yourself. Permethrin is safe for people once dry, toxic to cats on direct contact with wet treatment — let the clothes dry fully before the cat gets a sniff.

The combination of permethrin on clothing + DEET or picaridin on exposed skin is the most effective civilian protection there is.

When a head net beats repellent

Repellent is practical, but has its limits. It does not last forever, it rubs off with sweat, and it only covers skin you have applied it to. In the densest mosquito areas it becomes pointless to reapply every other hour — then a net is the better solution.

Head nets are the most used. They weigh 20–40 g, cost little, and are worn over a cap or hat so they are held away from the face. You breathe, see and eat through it. The best mesh density is around 600–900 holes per square inch — fine enough to stop midges.

Full-body nets (a bug jacket, or an anorak with an integrated hood) are relevant on particularly demanding bog trips in Finnmark. They weigh 100–250 g, and cover the upper body and head. Combined with close-fitting trousers and high socks.

What you pack

For a summer trip in the lowlands south of Trondheim, a small bottle of 20% picaridin or 30% DEET and a head net as backup. That covers 90% of Norwegian trips.

For Indre Finnmark, Hardangervidda in July, or a multi-day trip in bog terrain: 30% DEET, a head net, and preferably permethrin-treated clothing. Possibly a full bug jacket if your group includes anyone who reacts strongly to bites.

For a day trip in a tick zone (Southern Norway below the tree line, May to October): permethrin on socks and trouser legs, DEET on ankles and the back of the knee, and a routine tick check when you get home.

Next steps

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Text: Snuitide (2026).