Harvest has begun at the NIARC, early planted soybean are being harvested to allow the planting of winter wheat, weather permitting we should keep on harvesting from this date on. As crops matured in northern Illinois and dropped leaves on corn and soybean plants prior to harvest, producers have the opportunity to visually evaluate the effectiveness of their herbicide program in a challenging weed control year in 2012. Dry conditions, weeds "hardening off", applications taking place on weeds that were oversized, resistance or combinations of issues resulted in fields that no longer fit the "weed free" standard many farmers have grown to expect in the glyphosate era. For those who have listened to extension weed specialists and incorporated a soil applied herbicide in their program, the weedy fields may have come as a surprise and disappointment. Adding insult from Mother Nature, the soil applied herbicides that did not necessarily perform as expected following application could still be present at levels that may injure 2013 plantings due to limited rainfall. Despite frustrations, we can learn from and use 2012 as an educational tool to assist the decision making process for our 2013 weed management program. A basic tutorial on how soil applied herbicides function and what happens to the product after application will help temper our expectations.

• Weeds are most vulnerable at the seedling stage. Soil applied herbicides are most effective when they are in place prior to seedling emergence. If weeds exceed 2-3 inches, they often fail to be controlled by the soil applied herbicide.
• Ideal placement of soil-applied herbicides is the top 2 inches of the soil surface. This places the herbicide in close contact with most emerging and actively growing weed seedlings. This can be achieved via water (rainfall, irrigation) or tillage. Moving the herbicide too deeply in the soil profile can dilute the herbicide concentration and results in poor weed control.
• The potential for crop injury is generally considered to be greater for soil-applied herbicides in comparison to postemergence herbicides.As a general rule, smaller (younger) crops do not have the herbicide tolerance found in mature plants. Overapplication and overlapping can be critical. Accurate application rates are very important for weed control and crop safety.
• Soils with a higher cation exchange capacity, those with a higher organic matter or clay content will require higher rates of most soil applied herbicides because of the soils inherent absorptive properties.
• Herbicide adsorption varies with soil pH, soil organic matter content, and climate
• Herbicide carryover and crop injury are more likely in sandy and coarse soils where less herbicide is adsorbed to the soil.

To address evolving issues in weed control in northern Illinois a number of trials are underway at the Northern Illinois Agronomy Research Center. Specific studies include

• Herbicide systems for weed control in Roundup\Liberty Link Corn
• Pre and Post herbicides for weed control in corn
• Weed control systems for Roundup Ready soybean
• Tank mix and application timings for Giant ragweed control in soybean

This morning I had the opportunity to attend the Region II Illinois Soil and Water Conservation Districts meeting. I enjoyed visiting with regional representative Joe Bybee and many of the county representatives in attendance. One of the topics we discussed in relationship to cover crops was the looming weed issues in production agriculture in Illinois. For those who have attended meetings or followed the agriculture press; the drum has been beating on resistance issues in Illinois weeds. 2012 turned out to be a very challenging year for some and weeds are easily visible above the soybean canopy in a number of fields. While Giant ragweed is the primary weed at the NIARC, one does not have to travel far to find issues with members of the Amaranth family. Presently in northern counties the predominant amaranth weed species is Waterhemp. Importance of controlling this weed was clarified by a recent article authored by Aaron Hager. In the article it was shared that under warm conditions (86 degrees) Waterhemp seed becomes viable (will germinate) a mere 7 - 9 days after pollination. If you see a mature Waterhemp in your field that is not dead and is a female plant, it is likely that it has viable seed! The entire article including images can be accessed here

http://bulletin.ipm.illinois.edu/article.php?id=1705

Before leaving our discussion on members in the Amaranth family, a quick descriptor for today's image. My co-worker Robert Bellm shared a photo of a Palmer amaranth infested field near Collinsville along with the caption "NIARC in the future". His humorous comment is somewhat tempered by the fact that a Palmer amaranth was submitted and positively identified from Kankakee County. Still several miles away, but a lot closer than southern Illinois! Let's hope this image is not representative of northern Illinois until the distant future.

I expect few predicted the 2012 growing season. I had high expectations when trials went in the ground at the NIARC. Unfortunately, we have been reminded of the effect Mother Nature can have upon the livelihood of those involved in production agriculture. With precipitation she can be generous or not, and unless you invest in irrigation there is little one can do. There have been many suggestions followed by questions in recent weeks on products that could be applied to our crops to increase yield at best, or at the very least help them survive longer in hope of late season rains. Most of us realize, whether we want to admit it or not, what the crop needs is water. It is frustrating because that is out of our control. While we will not get the yields we expected at the beginning of the year, we will learn from the research nonetheless. We don't know when or if we will have a similar growing season to 2012, but if it does take place we will be better educated on what to expect and what may or may not be economically beneficial.

Several of you who attended the summer field day had the opportunity to see the weed competitiveness study by USDA weeds researcher Dr. Adam Davis. In this study Palmer amaranth and Shattercane seedlings were transplanted next to soybean to measure the competitiveness of these weeds on soybean yield as they mature. Several asked if introducing these troublesome weeds to northern Illinois was a sound idea (I cleaned the question up just a bit). For those who expressed concern, rest easy, the plot is being very carefully monitored by Vince Filicetti. At his behest, the Palmer amaranth was removed from the NIARC almost three weeks ago and the Shattercane will be removed tomorrow. In a year of things to worry about, this can be crossed off the list!