1 Dr. Jatinder S. Aulakh Valley Laboratory, Windsor, CT. The Connecticut Agricultural Experiment Station 153 Cook Hill Road, P. O. Box 248. Windsor, CT 06095. Phone: (860) 683-4984. Fax: (860) 683-4987. Founded in 1875 Email: Putting science to work for society Website: Horsenettle ( solanum carolinense L.)- Identification and Management in Connecticut Pastures and Rangelands By Jatinder S. Aulakh Horsenettle star shaped, have five white to pale-violet Other names: bull nettle/Carolina nettle/ petals, and are borne in clusters (Fig.)
2 2). sand brier Anthers at the center of the flower are Horsenettle is a perennial, rhizomatous, yellow, tubular structures. broadleaf plant ( ) that belongs to the nightshade family, Solanaceae. It is a highly difficult-to-control weed in grass pastures, meadows, and hay fields. Figure 2: AmCarolina Horsenettle flower cluster. Figure 1: A Carolina Horsenettle plant. Identification . An herbaceous, broadleaf plant with a stem height varying from 1 to 3 feet. Leaves are alternate, elliptic-oblong to oval with lobed margins, and the leaf midrib and petiole are studded with sharp prickles.
3 Horsenettle plants blossom (May to September), at about thirty days after the emergence. Flowers are m fruits/berries. Figure 3: Mature Horsenettle Fruits of Horsenettle , called berries, are Chemical control is perhaps the most initially green and turn yellow with maturity effective method for Horsenettle (Fig. 3). Each berry contains 40 to 170, management. Herbicides containing smooth, golden yellow, disc-shaped seeds. aminopyralid (Milestone, Milestone VM, Horsenettle propagates through seed and and Milestone VM Plus/Capstone), or creeping rhizomes.
4 Freshly produced seeds picloram (Grazon P +D) can effectively are dormant. The dormancy is broken by an control Horsenettle . However, current labels overwintering period. Optimum temperature for these products do not allow use on for germination ranges from 68 to 86 F Connecticut pastures and rangelands. (20 to 30 C). Products containing dicamba (Banvel or LIVESTOCK TOXICITY Clarity, 32 floz/ acre), triclopyr (Garlon 3A, Horsenettle is a toxic plant, however, reports 4 qt/ acre), triclopyr in combination with of animal poisoning are very rare.
5 Usually, fluroxypyr (PastureGard HL, 1 qt/acre), and most animals tend to stay away due to its 2,4-D in combination with dicamba sharp prickles that can cause injury in the (Weedmaster, 5 pt/acre ), or triclopyr mouth and food pipe. A toxic component, a (Crossbow, 4 qt/acre) in 10 to 100 gallon glycoalkaloid known as solanine, occurs in solution per acre can provide acceptable varying concentrations in different plant levels of Horsenettle control. Researchers at parts. Solanine can cause gastrointestinal the Louisiana State University obtained 87.
6 Irritation and nervous disorders in cattle. to 94% control of 12 to 15 inches tall Toxicity symptoms include bloating, Horsenettle with August applications of trembling, nasal discharge, salivation, and PastureGard (triclopyr plus fluroxypyr) at 1. breathing order of toxicity qt/acre. The University of Maine is: unripe berries > ripe berries> recommends a mixture of 4 pints of 2, 4-D. leaves>stems>roots the unripe berries ( lb/gal formulation) and 2 pints of are the most toxic and the roots are the least Banvel/Clarity (dicamba) per acre when toxic parts.
7 Toxicity is usually higher in late Horsenettle is in the flower bud stage (late summer to fall than in the spring. Cattle are summer or fall). Complete control of more susceptible than sheep. There are no Horsenettle will not be achieved with a reports, as yet, of toxicity to goats and single application of any herbicide. Long horses. term control is possible if herbicide applications are properly timed and repeated MANAGEMENT over multiple years. Remember, all these Mechanical control methods such as herbicides can severely injure or kill mowing, hoeing, and tillage have shown desirable forage legumes such as clover and very little success in Horsenettle control.
8 Alfalfa etc. Always make sure to thoroughly Extensive root systems make mechanical read and follow the herbicide label for control difficult. Tillage, in fact, helps in precautionary statements, directions for use, Horsenettle spread by distributing root rotational and re-entry interval restrictions, pieces. Cultural control will involve rotating prior to application. the contaminated field to Roundup ready corn or soybean. Sequential applications of GRAZING AND HAYING. glyphosate in Roundup ready crops at 1 RESTRICTIONS.
9 Qt/acre can effectively control Horsenettle Banvel/Clarity/Weedmaster (dicamba throughout the growing season. containing products): Do not graze lactating 2. animals for at least seven days after L.) in Virginia. treatment up to 1 pt/ acre, and 21 days after 2 pt/ acre, and 40 days after 4 pt/ acre of 142 Banvel. Remove meat animals from treated 2) Managing Silverleaf and Carolina areas 30 days before slaughter. There is no Horsenettles. waiting period between treatment and grazing for non-lactating animals. Do not ns/files/nr/2003 harvest grass for hay from the treated areas 3) Chemical weed control in grass at least 37 days after treatment up to 1 pt/ pastures.
10 Acre, and 51 days after 2 pt/ acre, and 70 days after 4pt/ acre of Banvel. Refer to the sture-course/lesson-4/life-cycle-of- product label for Banvel and Clarity plants/table-2/. ( ), 4) Weed management- Horsenettle . ( ), respectively, for additional information on weed-id/ Horsenettle safe use of these pesticides. 5) Control of Broadleaf Weeds in Pastures Using Non-2,4-D. Garlon 3A/Crossbow/ PastureGard Containing Herbicides. (triclopyr containing products): There is no waiting period between treatment and 72B28120-7869-4413-A196- grazing for non-lactating animals.