Host Plant – Any plant that furnishes subsistence for a plant pest. In the literal sense any plant that a bug or disease lives on is a host plant. In general usage, however, the term is used to describe a plant that is notorious for offering sustenance to any one bad pest. For example some grasses are hosts for chinch bugs in the south; and as barberries are hosts to rust which damages grain crops.
In mild winter climates when examined closely the undersides of some broad-leaved weeds during the winter act as wintertime host plants for aphids.
