- Pest Type: Weed
- Crops Affected: Wheat, Cotton, Potatoes, Soybeans, Corn
- Scientific Name: Solanum carolinense
- Pest Order: Solanaceae
Horsenettle is an erect perennial weed (0.3-1 m tall), spreading by rhizomes and adventitious shoots from roots. Stems and leaves have conspicuous spine-like prickles. Vegetative parts and fruit of horsenettle can poison livestock; however, reports of animal poisonings from horsenettle are rare because the prickly vegetation deters foraging.
Reproduction is by both seeds and rhizomes. Rhizomes may creep as far as 1 m from the central plant and send up shoots. Rhizome fragments can also be spread by cultivation. Shoots from rhizomes emerge around mid-May.
When coming from seeds, young plants have short stiff hairs on the stem and hypocotyl. Cotyledons are oval to oblong, about 1.2 cm long, hairy on the margins, glossy green above, and light green below.
Young leaves are alternate; the first two are sparsely hairy on the upper surface, with unbranched and star-shaped (4-8 rayed) hairs. Subsequent leaves are wavy or lobed, and hairy and prickly on both surfaces.
Stems are erect, angled at the nodes, somewhat branched, with sharp, stout, yellowish or white prickles (6-12 mm long), and star-shaped hairs. Leaves are alternate, 7-12 cm long and about half as wide, egg-shaped, with wavy or 2-5 shallow lobes on the margin and star-shaped hairs on both surfaces. Prominent sharp prickles are present on the veins, midrib, and petioles.
Dead stems bear persistent yellow wrinkled berries. Prominent prickles, conspicuous during the growing season, may fall off by winter.
Horsenettle is a weed of orchards, pastures, nursery crops, and other perennial crops. It may also be found in conventionally tilled agronomic crops, but especially reduced-tillage fields. This weed is particularly difficult to control in solanaceous crops, such as potato and tomato. Horsenettle grows on a wide range of soil types but thrives on sandy or gravelly soils.
Horsenettle is native to, and common in, the southeastern United States but has spread to the eastern and north central states, as well as west to Texas and into southern Canada.
The groundcherries resemble horsenettle but do not have the conspicuous prickles on the stems and leaves. The berries of groundcherry are enclosed by an inflated papery membrane.