Here are some observations on nightshade frost tolerance from the combine cab during soybean harvest this fall.
Check out the following blog post http://www.weedinfo.ca/weedID/?cat=4
It's a summary of photos that different people have sent in for Identification.
Every year in Ontario there are weed control failures with herbicides that can't be explained by inapproriate herbicide rate, weed stage or poor environmental conditions. In this case, certified crop advisors (CCA's), Industry representatives and producers send in weed seed samples to Dr. Tardif's lab at the University of Guelph to test for the posibility of herbicide resistance. In 2008 green and redroot pigweed, lambsquarters, green foxtail, eastern black nightshade, common ragweed and giant ragweed were tested for possible resistance to group 2 herbicides (i.e. Pursuit, FirstRate, Classic, Pinnacle), group 5 herbicides (i.e. atrazine) and group 9 herbicides (i.e. glyphosate). Once all the growth room data collected by Peter Smith (Dr. Tardif's technician) has been analyzed, I'll post the final results here. Stay tuned...... In the meantime check out the Ontario herbicide resistant weeds web page by clicking here.
Valtera (flumioxazin) is a pre-plant, pre-emergent soybean herbicide manufactured by Valent Canada that will be available to Ontario Soybean growers for the 2009 growing season. Valtera's strengths are the control of eastern black nightshade, lambsquarters and pigweed spp. For more information regarding this project along with Ontario public research data go to: http://www.weedinfo.ca/news.php?id=16.