Herbicide-Resistant Palmer Amaranth Field Day Report

Aug. 7, 2015

Palmer amaranth, a member of the pigweed (Amaranthaceae) family, is one of the most troublesome weeds in corn and soybean fields. Of particular concern is Palmer amaranth in south central Nebraska resistant to atrazine and HPPD-inhibiting herbicides (Callisto, Laudis, Impact). This is due to its proximity to intense seed corn production, which is heavily reliant on these herbicides for weed control.

To share research information on this topic a Herbicide-Resistant Palmer Amaranth Management Field Day was held Aug. 4 near Shickley. Amit Jhala, assistant professor and Nebraska Extension weed management specialist, organized and led the tour.  Roch Gaussoin, head of the UNL Department of Agronomy and Horticulture, gave the welcome address.

Curtis Thompson, a professor of weed science at Kansas State University, discussed Palmer amaranth identification, biology, and management in corn and soybean.

A total of 105 were in attendance including growers, crop consultants, extension educators, graduate students, industry representatives, and other clientele.

Jhala and team members demonstrated several projects for control of herbicide-resistant Palmer amaranth in field and seed corn and looked at efficacy, crop safety, and comparison of new herbicides in UNL's unbiased comparison trials. Stevan Knezevic, extension weed scientist, demonstrated projects related to dose response of palmer amaranth to atrazine and HPPD inhibitors (Callisto, Laudis, Impact). Graduate students Debalin Sarangi, Zahoor Ganie, Ethann Barnes, and Parminder Chahal showed a research project on various aspects of Palmer amaranth control in field and seed corn.

Featured projects were:

• Dose response of atrazine, Callisto, Corvus, Balance Flexx applied pre-emergence to Palmer amaranth in field corn
• Tank mixing atrazine with Callisto or Balance PRO at different rates for control of resistant Palmer amaranth
• Tank mixing atrazine with Callisto, Laudis, or Armezone post-emergence for control of Palmer amaranth
• Herbicide programs for resistant Palmer amaranth control in seed corn
• Management of Palmer amaranth in
• Roundup Ready Corn
• Liberty Link Corn
• Evaluating programs of Corvus or Balance Flexx followed by DiFlexx in Roundup Ready corn
• Understanding emergence of Palmer amaranth for most effective control
• Understanding effect of tillage on Palmer amaranth emergence
• Overlapping residual herbicides for Palmer amaranth control in field corn

The Field Day was sponsored by Nebraska Corn Board. Irvin Schleufer, Sharon Hachtel, Caleb Wilford, Wendy Morrison, Ian Rogers, Whitney Walters, and Lyndsay Drudik provided help with registration and tour logistics.

For more information, contact
Amit Jhala
Nebraska Extension Weed Management Specialist
402-472-1534
Amit.Jhala@unl.edu