The issue: Cutleaf Nightshade

Cutleaf nightshade (Solanum triflorum), native to western North America, is a summer annual that grows in a spreading mound that may reach two feet tall. The plants branch heavily close to the ground.

The green plants and juice from the berries and can clog harvesting machinery. It is commonly found in orchards, flowerbeds, vegetable gardens, cultivated fields, rights-of-way, and any other place the seeds drop. Being in the same genus as potatoes, tomatoes, peppers and eggplant, it can source of the pests and diseases that affect those crops.

Cotyledons are lanceolate and the true leaves are alternate, lobed and wavy. The white flowers have five petals and are borne in clusters with up to six blossoms—much like a potato flower. They bloom throughout the summer. The green berries are ¼ to ½ inch in diameter. All plant parts are toxic to livestock and humans.

Cutleaf nightshade spreads by seed and it germinates throughout the summer. A single plant may produce over 16,000 seeds. Fruit may continue to mature after the plant is pulled

Integrated pest management options:

· Prevention: Keep ditch banks free of seed-producing plants; clean equipment; use weed-free seeds.

· Mechanical: Hand dig plants before fruit develops; dispose of any fruiting plants; flame weed seedlings.

· Cultural: Natural mulch in flowerbeds 4 to 6 inches deep; weed barrier; solarization.

· Biological: None.

· Chemical: Effective herbicides depend in large part on the crop in which the weed is growing. Cutleaf nightshade is easier to control in grains and alfalfa, but not potato or tomato fields. Be sure the target weed and crop or landscape situations are listed on the product label. Always read and follow herbicide label directions.

Combine them:

These control options are all more effective when combined with the other efforts described.

For more information, contact Ron Patterson, University of Idaho Extension horticulture/agriculture educator in Bonneville County, at 208-529-1390 or rpatterson@uidaho.edu.

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