HPIPM:Silverleaf nightshade

Taxonomy

Domain	Eukarya
Kingdom	Plantae
Phylum	Magnoliophyta
Class	Magnoliopsida
Superorder	Asteranae
Order	Solanales
Family	Solanaceae
Genus	Solanum

Scientific Name

Solanum elaeagnifolium

Common Name

silverleaf nightshade

Silverleaf nightshade (Solanum elaeagnifolium)

Author: Tim Prather, University of Idaho, Department of Plant, Soil, and Environmental Sciences

Adapted from: Idaho Weed Resource webpage on silverleaf nightshade.

Identification and Life Cycle

Silverleaf nightshade (Solanum elaeagnifolium) is a perennial in the nightshade family (Solanaceae) that grows up to 3 feet tall. Cotyledons are gray-green and lanceolate. First leaves are oblong with wavy margins. The leaf surface is covered with star-shaped hairs giving it a gray-green color. Subsequent leaves are lance shaped, somewhat wavy along the edges, an inch or less in width, and up to 5 inches long. Stems are armed with a few yellowish thorns. Both stems and leaves are covered with downy hairs, giving the plant a silvery appearance. Flowers are about 1 inch wide with five bluish to lavender or occasionally white petals, surrounding five bright yellow anthers clustered in the center. Flowers are borne from midsummer until frost. Fruits are smooth, orange-yellow to dark colored, many seeded berries. The plant has extensive horizontal rhizomes that extend from the crown.

Habitats

Silverleaf nightshade grows along roadsides, cultivated fields, and disturbed sites.

Impacts

Twenty-one states have declared silverleaf nightshade a noxious weed, because it is toxic, reduces crop yields, serves as an alternate host for insect pests (Colorado potato beetle and Lygus bugs) and diseases of crop plants. Glycoalkaloids found in silverleaf nightshade can poison cattle and sheep. Concentrations of ripe silverleaf nightshade berries in livestock feed as low as 0.1 % of body weight produce symptoms in cattle.

Biology and Ecology

Silverleaf nightshade reproduces by seeds, creeping roots, and root fragments. Wind, water, birds, vehicles, machinery, agricultural products, and feces of grazing animals carry the seeds. Dried plants with berries break off and blow in the wind or may float long distances in water. Silverleaf nightshade stores large food reserves in its extensive root system. Vertical roots grow to 6 feet deep, and horizontal roots can establish daughter plants 6 feet away. These roots, which are deeper than those of associated crops (cotton, wheat, peanuts, grain sorghum), allow silverleaf nightshade to extract water deep in the soil profile. Plants will re-grow from severed roots at a depth of 4 feet. Root fragments as small as 3/8 inch will produce a new plant under favorable growing conditions. Silverleaf nightshade plants go dormant during the winter; the seedlings do not overwinter.

Management Approaches

Chemical and biological control can control silverleaf nightshade. Frequent mechanical control can suppress the weed.

Biological Control

A nematode (Orrina phyllobia), is available for biological control of silverleaf nightshade. The nematode causes galls to form on stems and leaves.

Mechanical and Cultural Control

Mowing silverleaf nightshade encourages multiple shoots when the plant re-grows. Removing above-ground parts every 2 weeks can prevent seed production. Cultivation must be frequent and thorough to control silverleaf nightshade.

Chemical Control

Silverleaf nightshade can be controlled with a number of herbicides.

Examples of herbicides that can be used to manage silverleaf nightshade

Consult herbicide labels for additional rate, application, and safety information. Additional herbicide information can be found at http://www.greenbook.net.

Herbicide Active Ingredient trade name	Mode of Action	Product per Acre	Application Time or Growth Stage
Alfalfa
Glyphosate	Inhibition of EPSP synthetase
*Roundup Original		2 quarts	Apply prior to crop emergence when 60% of silverleaf nightshade plants have berries. Apply fall treatments before killing frost.
Grass Grown for Hay or Silage, Pasture, Rangeland
2,4-D; dicamba	Action like indole acetic acid (synthetic auxins)
*Weedmaster		4 Pints	Apply when silverleaf nightshade is in full flower
Barley and Wheat
Dicamba	Action like indole acetic acid (synthetic auxins)
*Clarity		8 ounces	Apply when barley is in the hard dough stage and the green color is gone from the nodes (joints) of the stem. Best results will be obtained if application can be made when weeds are actively growing, but before weeds canopy.

The information herein is supplied with the understanding that no discrimination is intended and that listing of commercial products, necessary to this guide, implies no endorsement by the authors or the Extension Services of Nebraska, Colorado, Wyoming or Montana. Criticism of products or equipment not listed is neither implied nor intended. Due to constantly changing labels, laws and regulations, the Extension Services can assume no liability for the suggested use of chemicals contained herein. Pesticides must be applied legally complying with all label directions and precautions on the pesticide container and any supplemental labeling and rules of state and federal pesticide regulatory agencies. State rules and regulations and special pesticide use allowances may vary from state to state: contact your State Department of Agriculture for the rules, regulations and allowances applicable in your state and locality.

References

For more information and images please visit IPM Bugwood. http://www.ipmimages.org/search/action.cfm?q=silverleaf%20nightshade