From Dermatology Daily,, today, Mayr 25, 2016
In case you missed it.  This has been in the news :  Most Natural Mosquito Repellents Last Less Than An Hour Against Aedes Mosquitoes, Consumer Reports Finds. 
(5/24, Fox) reports on its website that “most so-called natural mosquito repellents do not last anywhere near as long as those containing synthetic chemicals, Consumer Reports found.” Of the six plant-oil-based insect repellents tested by Consumer Reports, five lasted an hour or less against Aedes  mosquitoes (among them,  the one causing Zika)