Tuesday, April 12, 2016

Cold Temperatures and Burndown Herbicides

by Bob Hartzler
     Professor of Agronomy Extension Weed Specialist
     Iowa State University


published April 11, 2016
                Integrated Crop Management on line newsletter






The weather forecast appears to be favorable for field activities so people will be anxious to get into the field. A concern for many will be the effect of the widespread freeze on the performance of burndown herbicides. Unfortunately, there is no simple blanket statement that can be made since the plant response will vary depending on weed species, weed size, and the herbicides used.


Postemergence herbicides

A statement found on most postemergence herbicide labels is ‘Apply when weeds are actively growing.’ This is by far the most important consideration in determining whether to apply a postemergence product. Most weeds that emerge in March are adapted to sub-freezing temperatures and will not be killed by frost; however, it takes time for them to recover from these events. Performance of herbicides will be reduced if applied too soon following a frost. How long does it take to recover? Again, no simple answer since it depends on the weed species, severity of the frost, and weather conditions that follow the freeze. Closely monitoring the weeds for evidence of new growth is the best way to determine recovery.


Tuesday, March 22, 2016

U of MN researchers seeking soybean growers to cooperate on study of impacts of seed treatments on soybean aphid and parasitic wasps

by Jonathan Dregni (Scientist), Robert Koch (Assistant Professor & Extension Entomologist), and George Heimpel (Professor)

Insecticidal seed treatments are used widely in soybean production. As with any new pest control technology we need to examine the potential for unintended consequences (see more at 
The Effectiveness of Neonicotinoid Seed Treatments in Soybean). University of Minnesota entomologists are looking for farmer collaborators willing to help study insecticidal seed treatments by allowing researchers to monitor populations of aphids and parasitic wasps in soybean fields planted with insecticide-treated and untreated seeds. Please contact Jonathan Dregni, U of MN scientist, if you or a neighbor would like to be involved, dreg0005@umn.edu or 651-207-3539.

Considerations when planting dicamba-tolerant soybean

by Lisa Behnken, Extension Educator, Fritz Breitenbach, IPM Specialist SE Minnesota, Jeff Gunsolus, Extension Agronomist, Weed Science, and Phyllis Bongard, Content Development and Communications Specialist, University of Minnesota

Monsanto's Roundup Ready 2 Xtend™ soybean, which is tolerant to both glyphosate and dicamba, is available for purchase this spring. While this will eventually offer another option for controlling glyphosate resistant and other tough-to-control weeds, it also brings up label and marketing concerns for the 2016 growing season.

Chomping at the bit yet?

prepared by Jochum Wiersma, UMN Small Grains Specialist

Although there is some snow in the forecast for tomorrow across much of Minnesota, the weather has been unseasonably mild and the frost is already out of the ground in many areas. The first reports of small grain being seeded reached me yesterday and that begged the question whether it is too early the seed small grains. In 2012, the last week of winter and first week of spring were also unseasonable warm. At that time I wrote a short article about the risks and rewards of early planting. Please check back here if you like reread the blog post and refresh your memory.

Thursday, January 14, 2016