This species, distributed in North America from Canada to Mexico, is also present in Cuba, Brazil, Hawaii, while it is not present in Europe. In 1935 it was introduced from Hawaii into Egypt to control the Pink Bollworm, Pectinophora gossypiella (Saunders, 1844) (Lepidoptera Gelechiidae), but it seems not established (Bey 1951, Yu et al. 2012).

Bracon mellitor lives on many hosts, mainly belonging to the Coleoptera Curculionidae and several families of Lepidoptera, especially Tortricidae, Pyralidae, Gelechiidae and Noctuidae (Yu 1997-2012; Yu et al. 2012). Among these species are included the already mentioned Paralobesia viteana and Lobesia botrana. The former was initially confused with Lobesia botrana (see e.g. Johnson and Hammar 1912), and it is likely that the record of Bracon vernoniae on Lobesia botrana reported by Leonardi (1925) originates from this mistake, since Marsh (1979) and Tillman and Cate (1989) did not include this moth among the hosts of this Bracon.