I think when one wants to see the world as black and white, it will be black and white regardless of what research is or is not available (not meaning you aimee).
“About 70 plant extracts were tested for their ability to repel the attacks of blood-sucking arthropods. It was found that a CO2 extract of the seeds of the Mediterranean plant Vitex agnus castus (monk’s pepper) can be used as a spray to keep away especially Ixodes ricinus and Rhipicephalus sanguineus ticks from animals and humans for at least 6 h. In addition mosquitoes, biting flies and fleas are also repelled for about 6 h.” http://link.springer.com/article/10.1007/s00436-004-1297-z
“The interest in the use of monoterpenes for insect pest and pathogen control originates from the need for pesticide products with less negative environmental and health impacts than highly effective synthetic pesticides. The expanding literature on the possibility of the use of these monoterpenes is reviewed and focused on the effects of limonene on various bioorganisms. Limonene is used as insecticide to control ectoparasites of pet animals, but it has activity against many insects, mites, and microorganisms.” http://www.oaj.tsv.fi/index.php/AFS/article/view/5697
There are more if one only took the time to actually look.
