Preemergence Corn Herbicides Applied in Dry Conditions Followed by Wet and Cool Growing Conditions

Preemergence Corn Herbicides Applied in Dry Conditions Followed by Wet and Cool Growing Conditions

 Are you are concerned with the amount of activity you are seeing with preemergence corn herbicide applications?  This video discusses some of what we are seeing with preemergence herbicide applications in our corn herbicide trials at Rochester, MN.  We will be following this trial during the 2017 growing season, providing periodic video updates.  If you like content in this format please subscribe to our YouTube channel: https://www.youtube.com/user/UMNCrops

Video at:
https://youtu.be/dKX5JY2rvgQ

May 18 Sauk Centre Hay Auction Summaries

by Dan Martens, Extension Educator, Stearns-Benton-Morrison Counties, 320-968-5077 or 1-800-964-4929, marte011@umn.edu.

Use links to see my summaries from the May 18, 2017 Sauk Centre Hay Auction

1. May 18, 2017 Summary- All tested loads sold, groups based on hay and bale type and quality

2. History of Selected Lots 

3. Graph of Selected Alfalfa hay groups.
            The 2016-17 season is the RED line now.

Continue reading for other sources of hay market information and crop information sources.

Herbicide Performance and Crop Injury with Cool Weather

Herbicide performance and selectivity are a function of how well the small grains and weeds that receive an herbicide are able to metabolize the active ingredient. The ideal temperature for applying most postemergence herbicides is between 65 and 85 F.  However, the temperatures following herbicide application will largely determine crop safety as the plant’s metabolism slows during cool or cold conditions. This extends the amount of time required to degrade the herbicide in the small grain plants. Rapid degradation under warm conditions allows crop plants to escape herbicide injury.

 Wild oat is more sensitive to the ACCase herbicide fenoxaprop during cool rather than warm/hot conditions but also may cause some crop injury. Green and yellow foxtail are warm season grasses and their uptake and metabolism is reduced under cold conditions resulting in reduced control.  ACCase herbicides provide better grass control in warm weather when grasses are actively growing

 Cold temperatures, including freezing conditions following application of bromoxynil may increase crop injury with little effect on weed control. The plant growth regulator herbicides, 2,4-D, dicamba, MCPA, clopyralid and fluroxypyr have adequate crop safety and provide similar weed control, but the rate of weed decline and control is slowed when cold temperatures follow application.

 Refer and follow each herbicide label for specific information about weather conditions including adjuvant use during stress conditions.

Alfalfa Harvest Alert Data May 25, 2017

by Dan Martens, UM Extension, Stearns-Benton-Morrison Counties, 320-968-5077, marte011@umn.edu

Click on Alfalfa Harvest Alert May 25 for field and lab information on Thursday May 25, updated on Friday May 26 about 8 PM. No info from 2 farms, lab info not back from 1. 1 farm reported cutting on Thursday and Friday, could be others. Some watching to see how the weekend weather turns out. Some looking for a little more growth on fields if they can.

Have you lost your N in the past week?

Widespread wet weather and yellow corn has caused concern among Minnesota farmers regarding the status of their nitrogen fertilizer.  Extension Educator Brad Carlson discusses the processes of nitrogen loss from wet weather in context to this past week's weather in the new video, Spring 2017 nitrogen concerns

Additional resources can be found on the University of Minnesota Nutrient management website at  http://www.extension.umn.edu/agriculture/nutrient-management/ and the Extension Crops website, z.umn.edu/crops.

You may also like UMN Extension Nutrient Management on Facebook and follow us on Twitter.

Support for this project was provided in part by the Agricultural Fertilizer Research & Education Council (AFREC).

NDAWN Network Adds Temperature Inversion Alerts

The North Dakota Agricultural Weather Network (NDAWN) provides current weather data, climatological records, and is the backbone of growth and development models in North Dakota and Northwest Minnesota.  This, for example, includes the orange wheat blossom midge emergence model and the small grains disease development risk models.  This summer a new tool is being added to the suite of NDAWN applications, namely a temperature inversion alert.

Inversions are areas of the atmosphere where temperature increases with height. This stable air mass results in low wind speeds and horizontal flow. When spray droplets are dispersed in this environment, the smallest drops may not make it to the ground and can end up floating for long distances before settling in an entirely different area, including someone else's field.

This meteorological phenomenon can be a headache when applying pesticides. in particular herbicides. Even though many of you are aware of the existence of inversions, it is not that easy to determine if they are happening.

After nearly a year of testing, NDAWN has begun installing their inversion instrumentation across the NDAWN network. Currently the Fargo, Carrington and Langdon NDAWN sites are equipped to detect temperature inversions, with six more being added later this year.  The instrumentation consist of tall pole with thermometers mounted at approximately ground level, 3 and 18 ft. The difference in temperatures will allow inversions to be recognized, and the corresponding data will then be instantly published on the NDAWN website.

To access, users should go to the “NDAWN Center” page and click on the “Show tower measurements” checkbox. Users will have access to the temperatures and be notified with a red number and “!” symbolizing that an inversion is in place and they should act appropriately. The network’s real-time data stream will allow users access to these updates every five minutes.

Although the system can identify an temperature inversions at the NDAWN station your conditions in your field may differ. This information is a decision-support tool and you need to evaluate local conditions in your field to ensure that you can apply the pesticides safely and according to the label directions.

Are soil residual herbicides necessary in late-planted soybean: What are your options if soybeans have emerged?

Jeff Gunsolus, Lisa Behnken, and Fritz Breitenbach

Figure 1. Emerging soybeans at Rosemount ROC on May 24, 2017. Photo: Dave Nicolai

Application of a residual herbicide prior to planting or emergence of the crop is an effective and highly recommended weed management strategy and also a key tool in managing herbicide resistance. Soil-applied residual herbicides are especially important to address tall waterhemp. Tall waterhemp has an emergence period of long duration into the summer and some biotypes are resistant to two to three different herbicide sites of action (SOA). Therefore, it is economically wise to include a soil residual herbicide at the time of planting. However, recent rains have delayed some farmers from getting onto newly planted fields in a timely manner. What are some of our options if soybeans emerged before a preemergence herbicide application was made?