Thursday, June 9, 2016

Watch for Cereal Aphids in Winter and Spring Wheat / Small Grain Survey Maps for Minnesota and North Dakota

Cereal aphid Infestation levels in recent weeks 
illustrate the northward movement to HRSW 
from the earlier infestations of Winter Wheat in 
southern MN.
Field reports from Minnesota (MN) indicate that the cereal aphids reported in winter wheat in early May, many of which were treated at the time of herbicide/fungicide applications, are now moving to spring wheat in those southern areas of MN. Surveys are also detecting movement and colonization northward to central and northern HRSW areas of MN. In North Dakota and Minnesota, IPM Scouts are finding these increasing populations, so continue to scout fields for cereal aphid population buildups.

Small Grain Survey maps are now available on a weekly basis and can be accessed for viewing:
  • crop development
  • disease observations, both incidence (% infested plants) and severity (level of infection)
  • insect infestations

Links to the survey maps are at the top of the right column or can be found at:  

Wednesday, June 8, 2016

Weed identification

Whether you are a novice or a veteran, if you need some references for weed identification, here are some resources through University of Minnesota Extension. There are also many references available for your smartphone that you can take to the field.

Got weeds? U of M Extension has resources

Managing herbicide resistance and controlling resistant weeds is a challenge. The U of MN Extension Crops Team is offering new video and web resources to help manage these difficult to control weeds:
  • Weed management website – includes resources on herbicide resistance management, weed identification, herbicide application and chemistry, and research reports.
  • Herbicide resistant waterhemp (video) – Waterhemp has an extended emergence pattern, making it difficult to control. Results from a 2015 trial demonstrating the effectiveness of layering residual herbicides for herbicide-resistant waterhemp control are shown in this video.
  • Herbicide resistant giant ragweed (video series) – Due to its large seed and early emergence, giant ragweed can be difficult to control. This video series describes a study looking at alternative management practices to control this herbicide-resistant weed.

To see additional videos from the U of M Crops Team, visit:

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, or 651-207-3539.