One of the plants collected by Antonio de Benedictis, director of the Department of Agriculture in Asmara, was the holotype of Ocimum forskolei, possibly the closest relative of sweet basil, O. basilicum. The holotype is the actual physical specimen on which the formal description of a new species is based, and that’s a picture of the herbarium sheet of de Benedictis’ specimen, collected at Dogali in Eritrea  nine years before he met Vavilov. 
Local people in Eritrea use O. forskelei against “nuisance insects,” including mosquitoes, and it works. Furthermore, a combination of O. forskelei and human odour tends to divert mosquitoes with catholic tastes to goat odour, if goats are nearby. It also diverts them to human odour without the basil. The message is clear: if you want to reduce mosquito bites while out and about in Eritrea, put some O. forskelei at the head and the foot of your bed, and keep a goat nearby.
I doubt Vavilov knew that.