When the plows and gardens of the east moved westward - when the rutted wagon trails traveled deeper and deeper into the sod and further and further into the far west, certain plants and insects backtracked, following the pathway of cultivation to the east.
Solatium carolinense L.
June - August Pastures.
One of these was the yellow-floweerd buffalo-bur (Solarium ros-tratum) and another was the closely related white or lavender flowered horse-nettle. With these came the potato beetles, and it is believed that through the distribution of these plants this insect came into the farms and gardens of the eastern states which never had known them before.
Horse-nettle is a thorny weed with small, yellow, tomato-like fruits the size of a large cherry. They are not enclosed in a husk, as the ground cherry is, with which it is sometimes confused. The plant is a member of the Tomato-Potato family, the nightshades or Solanums, and the flower, resembling those of this family, in itself is crisp and pretty.
Potato beetles feed as avidly upon the spiny leaves of the horse-nettle as they do upon the more succulent leaves of the potato. The beetles knew these wild Solanums Long before they learned to devour potato plants. From the Great Plains and the foothills of the Rockies, the horse-nettle, with its usual accompaniment of beetles, then came eastward into plowed land. The potato fields were invaded.
Horse-nettles are common in waste places in Illinois. The yellow fruits are. noticeable in late summer and autumn. They are eaten by only one mammal, the sheep, which seems unharmed by a degree of toxicity found in horse-nettle seeds and leaves. The fruits are not recognized as an edible wild fruit for human consumption.