The Nightshade Family

Nightshades are part of a very large and interesting family of plants called Solanaceae. Potato, tomato, and peppers are usually recognized as Solanaceae, but there are actually over 2000 species in the family. This family (sometimes called the nightshade family) has a particular star-shaped flower arrangement that looks like the rays of the sun, thus the family name Solanaceae. Some Solanaceae plants are known for being poisonous, while others are known for their medicinal uses. 

📸: @Nazanin Esfandyarpour via Canva/Featuring a close-up shot of European Black Nightshade (Solanum nigrum) fruiting body (Left); @lnzyxr via Canva/Featuring European Black Nightshade flower (Right).

Common Nightshade Weeds

There are a number of nightshade weeds that can be a problem in crop production. Nightshades are a particular problem in Solanaceae crops such as tomato and potato, as most herbicides safe for a Solanaceae crop are also safe for a Solanaceae weed. Being in the same family as some important crops means that nightshades can host problem insects such as Colorado potato beetle and aphids, as well as diseases such as early and late blight, which are important in potato and tomato.

Common Nightshade weeds in the US are:

1. Eastern Black Nightshade (Solanum ptycanthum): This is the most prevalent nightshade weed in the Midwest. One telltale identification clue is the shot holes in leaves from flea beetle feeding. It is found anywhere east of the Rocky Mountains. As a weed in corn and soybeans, you might have noticed it is very frost-tolerant, allowing the juicy black berries filled with seeds to cause a mess at harvest.

📸: BASF employee/Featuring a close-up shot of Eastern Black Nightshade seedling.

2. Hairy Nightshade (Solanum sarrachoides): This species is by name covered with hair, giving it a silver color, and is found across the US.

3. European Black Nightshade (Solanum nigrum) is found primarily on the Pacific coast.

📸: @Ines Carrara via Canva/Featuring a close-up shot of European Black Nightshade (Solanum nigrum).

4. Cutleaf Nightshade (Solanum triflorum) is just the opposite of European Black Nightshade. Cutleaf Nightshade is found almost anywhere except the Pacific coast.

5. American Black Nightshade (Solanum Americanum): Common across much of the US, but more often found in wooded areas that corn and soybean fields.

📸: @jessicahyde via Canva/Featuring a close-up shot of American Black Nightshade (Solanum Americanum).

Controlling Nightshades in Corn

Most broadleaf corn herbicides are effective on nightshades, but it is important to know that there has been some herbicide resistance reported to Eastern Black Nightshade with group 5 atrazine herbicide. Preemergence applications of group 15 Outlook^® Herbicide or Zidua^® SC Herbicide, group 14 Verdict^® Herbicide, as well as post-applications of group 27 Armezon^® Herbicide or Armezon^® PRO Herbicide, and group 4 Status^® Herbicide, offer good control of nightshade. Post-applied dicamba, 2,4-D, or glyphosate also offers good control of smaller plants.

Controlling Nightshades in Soybean

There has been some herbicide resistance reported to Eastern Black Nightshade with the group 2 imidazolinones herbicides. In soybeans, preemerge applications of group 15 Outlook™ herbicide or Zidua^® SC Herbicide, group 14 Sharpen^® Herbicide or Verdict^® Herbicide, as well as post-applications of group 10 Liberty™ herbicide, group 4 dicamba or 2,4-D, and group 9 glyphosate will provide good control.

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