In winter in Indiana, our soybean aphids (Aphis glycines) are overwintering as eggs on its secondary host, buckthorn. Soybeans, soybean aphid and buckthorn are all non-native plants imported separately from Asia. Buckthorn was introduced as a horticultural plant that became invasive. Thus, when soybean aphid arrived in North America, both its primary and secondary hosts were present.
In late spring, aphids on buckthorn produce wing forms that colonize emerging soybeans. The…
Source: Living With Insects Blog