Its important to know your nightshades -- particularly the difference between eastern black nightshade and black nightshade -- for two reasons, says Richard Zollinger, NDSU extension weed specialist:
1) Up until a couple of years ago no one really differentiated between
black and Eastern black nightshade because we thought whatever controlled Eastern black would control black nightshade.
For simplicity we said that North Dakota had only Eastern black nightshade. Then two things happened.
Richard Greenland, who runs the Experiment Station in Oakes called and said he had been using Matrix in potato for Eastern black nightshade control but Matrix no longer controlled it. Matrix is labeled in potato for partial control of hairy nightshade. Some speculated it had activity on Eastern black nightshade.
Then, an article was printed in the Weed Science Journal summarizing We suspected that Richard killed his Eastern population and replaced it with black nightshade. This was the first documented case of black nightshade in North Dakota. What was thought to be Eastern black nightshade is common in potato production in North Dakota and Minnesota. If Matrix does not control the nightshade it might be black instead of Eastern black nightshade
research where Matrix gave >95% Eastern black nightshade control, 50 to 99% hairy
nightshade control, and 0 black night shade control.
2) Eastern black nightshade resistance to Raptor and Pursuit has been confirmed in many areas in North Dakota and Minnesota. If the nightshade is not controlled, you will need to distinguish if it is black nightshade or resistant.
Nightshade control in soybean/dry bean:
PPI and PRE herbicides: Soybean: Authority, Outlook, Python, Sonalan. Drybean: Outlook, Sonalan.
POST herbicides: Soybean: Cobra, Flexstar, Pursuit, Raptor, Ultra Blazer, Liberty (Liberty resistant Soybean), glyphosate and Extreme (Roundup Ready Soybeans). Dry bean: Pursuit, Raptor, Reflex.
Notes: Basagran may control hairy nightshade, but not Eastern black nightshade. Basagran, Cobra, and Ultra Blazer control only small nightshade. Flexstar/Reflex gives poor hairy nightshade control. Only Authority, Python, Extreme and Pursuit gives residual control of multiple flushes but these herbicides may restrict seeding of some crops one or more years after application.