Funny story, about 8 years ago I went with 3 others into French Canyon, Mid July, right at the worst of the skeeter season. Once of the guys had brought the "Natural" Lemon Eucalyptus spray. It smelled really nice. The rest of us smelled like HAZMAT from the deet.
By day 2, we were all giving him a couple spritzes of deet, because while the Lemon Eucalyptus "Worked"... it apparently worked not as a "repellent" so much as a "Marinade" - once it soaked in for 15-20 minutes, he was ATTACKED. Poor guy had like 47 bites on ONE ARM.
It DID seem to work SOMEWHAT on clothing, hats, etc...
I know DEET works. I stick with DEET.