Eastern black nightshade
Controlling eastern black nightshade in soybeans
Whether you’re growing herbicide-tolerant soybeans or IP food-grade soybeans, eastern black nightshade (EBN) can be a tough weed to control. That’s partly because it tends to emerge in late spring, after other important weeds, and partly because it is often mistaken for redroot pigweed, which has a wider window of control.
It is absolutely critical to control eastern black nightshade upon its early stages because it can move incredibly fast, taking only six weeks to go from germination to seed production.1 It’s also a prolific seed producer, averaging 10,000 seeds per plant.2
Controlling eastern black nightshade in soybeans requires a good plan centered around early weed removal.
- Stop EBN before it can start. Pre-plant or pre-emergence herbicides are key. While it may emerge later than other key weeds, eastern black nightshade still appears during the critical weed-free period for soybeans (first to third trifoliate), so must be controlled early to protect yield.
- Know what you’re looking for. Check the underside of the leaf. If it is deep purple, it’s likely eastern black nightshade, not pigweed, which has a light violet colour. As well, nightshade cotyledons are oval to diamond-shaped, while pigweed cotyledons are long and narrow.
Control late flushes. Because seeds are easily dispersed by birds or on equipment, late flushes of eastern black nightshade are possible. If berries are in the field at harvest, they’ll burst going through the combine, staining soybeans enough to make them unmarketable, particularly IP soybeans where appearance can matter a lot.
Commenza™ herbicide has three modes of action (Groups 2, 5 and 15) to control of a wide range of broadleaf and grass weeds while managing resistance. Registered for use in IP and herbicide-tolerant soybeans systems, Commenza can be applied pre-plant, pre-plant incorporated or pre-emergence for early nightshade removal.
Freestyle™ herbicide has two Group 2 active ingredients for enhanced control of tough broadleaf and grass weeds, including eastern black nightshade. Freestyle can be applied in both IP soybeans and glyphosate-tolerant soybean systems.
- IP soybeans – apply Freestyle pre-plant to pre-emergence only. Tank mix with glyphosate.
- Glyphosate-tolerant systems – Freestyle can be applied pre-plant, pre-emergence and early post-emergence to catch later flushes.
To sum up
Eastern black nightshade is a growing problem across soybean-growing regions. This annual weed must be controlled early to protect soybean yields, but be vigilant for late flushes, which can damage crop quality and marketability. Brush up on your weed identification skills because eastern black nightshade seedlings look a lot like pigweed seedlings but, as they develop faster, you need to act faster when you see it.
1Ontario Ministry of Agriculture, Food and Rural Affairs. Annual nightshades. https://www.ontario.ca/page/annual-nightshades
2Michigan State University. Eastern black nightshade. https://www.canr.msu.edu/weeds/extension/eastern-black-nightshade