(journals.biologists.com)
The exact mechanism is not completely understood, but it's thought that DEET works because it interfere's with mosquitos ability to locate their prey. It is not thought to discourage bites as "they don't like the taste", just by interfering with sensing.
A newer repellent, Picaridin, not only interferes with locating prey, but actively deters mosquitos like pepper spray mace. It's an engineered molecule, derived from a compound called piperine, a substance found in black pepper plants.
Studies show that "Picaridin is as effective as DEET", but my personal experience is it is about twice as effective as DEET.
I spend an enormous amount of my free time outdoors and I can attest that Picaridin is far more effective than DEET for both mosquitos and ticks (we have two main species in the Kansas/Missouri/Arkansas region, others are present but less common).
As a personal data point, I had a friend trip on a hike this spring and fall into a grassy/bushy area. He did not put any repellent on. When we stood up, he was _covered_ in ticks. We got back to the truck and started peeling them off him, probably 15+ plus we flicked off or crushed. Unfortunately, we kept finding more, so we tried spraying Picaridin after the damn things hated that stuff so bad they jumped or fell off instantly.
You do not want to get Picaridin in your eyes or mouth, holy shit, that stuff is like bear mace. Also make sure you're downwind when you're spraying, your friends with appreciate that.
The other advantage of Picaridin is that it does not melt certain plastics. If you have life saving gear made of certain plastics, DEET can melt many times of plastics! (Notably some PVCs, polycarbonates, acrylics, acetates, and elastics).
Edit: thought I'd include a link to a study about this as it's not well known. https://www.cell.com/current-biology/fulltext/S0960-9822(19)...
The simple answer would be to add a natural strongly repellent gentle oil to the DEET spray.
Mosquitoes attracted to DEET will die because of the insecticide. Usually, for personal protection, we tend to prefer repellents, as we don't want to get bitten, killing the mosquito after the fact is not very useful. But here, the idea is to put some evolutionary pressure against mosquitoes not repelled by DEET.
There are also repellants other than DEET. Icaridin being the best alternative. It is almost as effective as DEET without many of its drawbacks. Some essential oils too, as you said, but I don't think any of them have the effectiveness of icaridin or DEET.
They already loved that shit.
[1] https://www.consumerreports.org/health/insect-repellent/oil-...
I’m not saying you have to use it; it’s good news for people who have concerns about other chemicals. It works—less effectively, but it works.
“Repellants containing (..) oil of lemon eucalyptus have also been found to be effective.”[1]
[1] Iowa Department of Health, “Controlling Spread of West Nile Virus“ https://hhs.iowa.gov/health-prevention/providers-professiona...
I think the theory is that each post identifies with a certain topic, e.g. DEET, which identifies with a cultish subset of users surrounding that topic. There is no broad academic curiosity among the cult's members, and they suppress all competing topics as to them they represent other cults.
Go ahead, hose yourself down with Lemon oil, citronella, oil, or lemon eucalyptus oil. They simply do not work.
Also, the oils in question work reasonably for bug control, just for a lesser duration, requiring more routine reapplication. When you say they do not work, that's true only for the gap between how long the oils work versus how long ≥35% DEET works. And the concentration matters for both.
Until, of course, they learn to like the replacement oil. At which point, break back out the DEET!
"Evolution! Can you give me capsaicin, to deter mammals? I want birds to spread my seeds!"
Picaridin gives me worsened tinnitus, so I can't use it unless maybe I slowly try to condition myself to it over a week. DEET doesn't.