Progress regarding weed management extension and field research activities have progressed as planned since last quarterly report. Field research plots were completed and analyzed. Field projects included the soybean herbicide demonstration plots at Volga, NE Station, and the SE Station. Research projects included new herbicide evaluation studies, timing of dicamba or 2,4-D drift on soybeans, dandelion control in no-till, scouring rush control, kochia seed bank management, and volunteer soybean competition and control in corn. Results from these studies were printed in our research results publication that has been distributed to producers, industry representatives, and pesticide applicators. Approximately 500 copies have been distributed at this time. Research results were also posted on our searchable database at http://www.sdstate.edu/ps/weed-mgmt/weed-mgmt-crops.cfm.
We have been screening weeds for glyphosate resistant biotypes in the greenhouse. Our biennial wormwood sample sent in from the Conde area was not glyphosate resistant. That is a relief as that weed could be very difficult to control in Roundup Ready soybeans if it was glyphosate resistant. One kochia sample was confirmed as resistant, which adds to our list of confirmed resistant biotypes.
However, kochia escapes were common in central SD this year indicating that glyphosate resistance may have expanded greatly. We still have samples of lambsquarters and waterhemp currently being screened, results are being evaluated with one of the waterhemp samples looking like it is glyphosate resistant and the lambsquarters sample looking like it is not resistant to glyphosate treatments. We will continue to screen weeds from suspect fields as requested.The soybean herbicide fact sheet has been updated and approximately 3,000 copies printed. This year, we combined the herbicide, insecticide, and fungicide information to create a more comprehensive guide for pest management in soybeans. Over 2000 copies have been distributed to farmers and industry representatives at meetings, training events, and as requested. Of these over 1600 were handed out at the Commercial Pesticide Applicator Certification meetings in January and February 2013.