A. Thanks for the suggestion. Thai scientists have tested herbal oils as mosquito repellents and found that basil oil is effective for about two and a half hours (Southeast Asian Journal of Tropical Medicine and Public Health, July,2010).

From Graedon's website:

Q. You've written about natural ways to repel bugs. I use basil, the strongest member of the mint family and one I grow in my yard. At home, I just brush the leaves on one of the plants and I have no trouble from bugs while eating outside. I take a couple of leaves to an outdoor concert and brush them on my arms and legs. I am bug-free for two or three hours of enjoyment.