There is a price of admission to the most beautiful corners of the Top of the South, and it is paid in small, itchy instalments. The sandfly — namu, if you want the local name — is the one creature standing between you and a perfect evening by the water. You cannot beat them entirely; nobody has. But you can absolutely stop them ruining the trip, and the gap between a happy camper and a miserable one is mostly knowing a few things the namu would rather you did not.
Know Your Enemy
It Is Only the Females, and Only Near Water
Here is the first thing worth knowing: the sandfly that has been feasting on your ankles is female. The males get by on nectar and cause nobody any trouble at all. The females need a blood meal to develop their eggs, which is why they are so single-minded about finding you, and so hard to wave off.
They are weak fliers, so they hunt low and slow — ankles, wrists, the back of the neck when you bend to light the cooker. They breed in running water and damp ground, which is the cruel joke of the Top of the South: the namu are thickest exactly where the scenery is best. Riverbanks, estuaries, bush-fringed beaches, the edge of a clear stream you have driven two hours to swim in. If the spot looks like a postcard, assume the sandflies found it first.
Where the Top of the South Bites Hardest
Not all of the region is equal. The worst of it sits where bush meets water and the air goes still. The Golden Bay side — Wharariki, the Wainui and Totaranui ends of the country, the bush campsites around Takaka — can be genuinely fierce on a windless evening. The Kahurangi tracks, the Heaphy in particular, are notorious enough that people plan around them.
Estuary edges and river mouths anywhere from Marahau to the Marlborough Sounds will find you. The kinder places are the open, breezy ones: Nelson city, Tahunanui, Rabbit Island, anywhere moving air keeps the sandflies grounded. As a rule, the more sheltered, shaded and damp a place feels, the more you will pay for being there. The exposed, sunlit, breezy spots are your reprieve.
Timing and Wind
The Dawn and Dusk Tax
Sandflies keep office hours you will come to resent. They are at their worst at dawn and dusk, and they ramp up fast on a still, overcast day when the light is flat and the air sits heavy. The middle of a hot, bright day is usually the quietest stretch.
That is why the experienced campers do their swimming and their sitting-about between late morning and mid-afternoon, then retreat behind mesh when the sun drops. Pay the dusk tax knowingly. That golden half-hour when the light goes soft over the water is also the half-hour the namu come out in force, so either cover up before you wander down for the sunset, or accept that you are the entertainment and they are the audience.
The Breeze Is Your Best Mate
The single most useful thing to understand about sandflies is that they cannot fly in wind. A breeze of even ten or fifteen knots grounds them completely. This is the one piece of free advice that changes a trip.
When you are choosing where to put your chair, your tent or your picnic, choose the spot with airflow — the breezy end of the beach, the open paddock rather than the bush edge, the headland rather than the hollow. On a dead-calm day you can sometimes make your own relief with a small battery fan at the tent door, because they genuinely will not push through moving air. And when the wind drops at dusk and they descend, treat it as your cue to move, cover up, or get behind the mesh, not to tough it out.
What Actually Works
Repellent That Earns Its Place
You want a repellent with a proper active ingredient, not a scented lotion that smells nice and does nothing. DEET is the old reliable and it works; a concentration around twenty to thirty percent is plenty for sandflies and lasts a few hours before you need to top up.
Picaridin is the newer option, near enough as effective, less greasy, and it will not melt your sunglasses or your tent fly the way strong DEET can — worth knowing before you slather it on and lean against something you care about. Whatever you choose, the trick is coverage and timing: do the ankles, feet, wrists and neck, reapply after a swim or a sweat, and put it on before you need it rather than after the first bites. Once they have started on you, repellent stops the next wave but does nothing for the welts already coming up.
Cover Up, Light and Loose
Repellent handles the exposed skin; clothing does the rest, and on a bad evening clothing is the better defence. Long sleeves and long trousers in light colours — sandflies, like a lot of biting insects, go for dark fabric — and loose enough that they cannot bite through where the cloth sits against you.
Cover the ankles properly, because that is where they concentrate and where a thin sock does not help. A lot of seasoned Top-of-the-South campers keep a dedicated sandfly-hour outfit by the tent door: light long-sleeve, long pants, the lot pulled on at dusk without thinking about it. You will look like you are dressed for a different season than everyone who just arrived. You will also be the one who is not slapping their own neck through dinner.
At Camp and After the Bite
Pitching to Beat the Namu
Where you put the tent decides how the evenings go. Pitch on the breezy, open side of a campsite rather than tucked into the sheltered bush corner that looks so inviting at check-in — that corner is sheltered for the sandflies too. Keep some distance from standing water, the stream edge and the densest scrub.
If your tent or awning has mesh, use it religiously. Zip the inner closed during the day so the tent is not full of them by dark, and get into the habit of the quick in-and-out so you are not holding the door open while a dozen file in behind you. A screen house or an awning with mesh sides turns the worst hour of the day into a non-event, which is why you will see the old hands sitting comfortably behind theirs while the newcomers eat standing up and swatting.
When They Get You Anyway
You will still get bitten — everyone does, and a fresh sandfly bite is often barely noticeable, which is the trap. The reaction builds over the next day or two, and that is when the itch arrives and settles in, sometimes for the better part of a week.
The golden rule is the hardest one: do not scratch. Scratching breaks the skin and turns an itchy spot into an infected one, which on a camping trip is a genuine nuisance miles from a chemist. An antihistamine takes the edge off, something cooling helps, and cold water or ice settles a fresh crop. The bites on your ankles and feet will be the slowest to forgive you. Keep them clean, keep your hands off them, and remind yourself, every single summer, that next time you will put the repellent on before the first one bites.
None of this will give you a sandfly-free holiday, because there is no such thing in this part of the country. What it will give you is the upper hand: the right spot, the right timing, repellent on before the biting starts, and the good sense to be behind the mesh when the wind drops at dusk. Do that, and the namu become a background fact of camping rather than the thing you remember about the trip. The scenery, after all, is worth a few bites — just not as many as you collect by turning up unprepared and optimistic.