Considerations for Weed Management in 2016

Here is the final installment of considerations for weed management in 2016.

 

Steps for Successful Weed Management in Glufosinate-Resistant (Liberty Link) Soybean

 

Step 1:

Plant Liberty Link soybean seed into a weed-free seedbed

Achieve a weed-free seedbed through the use of:

                          1) Preplant tillage

                          2) Effective burndown herbicide(s)

                          3) A combination of tillage and burndown herbicides

 

Step 2:

Select and apply within 14 days of planting a soil-residual herbicide that targets your most problematic weed species.

For waterhemp or Palmer amaranth, select a product containing the active ingredients from one of the following categories of control:

Excellent                                 Good                                                 Acceptable

sulfentrazone                         pyroxasulfone                                   S-metolachlor/metolachlor

flumioxazin                             metribuzin                                         acetochlor

                                              fomesafen+metolachlor                     dimethenamid

                                                                                                        pendimethalin

*Excellent: greatest efficacy on Amaranthus species and longest residual control

Good: good efficacy on Amaranthus species, residual control generally not as long

Acceptable: stronger on grass species but with some activity on Amaranthus species

 

Step 3:

Apply Liberty at 32 fluid ounces per acre when waterhemp or Palmer amaranth are less than 4 inches tall. Be sure to apply in a minimum of 15 gallons per acre carrier volume with nozzles that produce a medium droplet. Include AMS (8.5 lb/100 gallons) with all applications. Add lactofen-, fomesafen-, or acifluorfen-containing products for a second site of action against PPO-susceptible Amaranthus species.

 

Step 4:

Scout treated fields within 7 days after application. If control of waterhemp or Palmer amaranth was not complete, or if another flush has emerged, retreat with 22-29 fl oz plus AMS. Rogue any survivors from the field before the plants begin to flower.

 

 

 

Helpful reminders:

1) Liberty is NOT Roundup. Applying Liberty with the same equipment set-up used for applying Roundup increases the likelihood of performance complaints.

2) Liberty works best with bright sunshine and high humidity. Avoid spraying after 6:00 p.m.

3) Ensure thorough coverage of weeds with carrier volumes between 15–20 gallons per acre. Applications made at higher gallons per acre result in fewer performance complaints.

4) AMS is the most reliable spray additive. Add a minimum of 8.5 lb/100 gallons.

 


Considerations for Weed Management in 2016

 

Here is the third installment with additional considerations for weed management in 2016.  The final installment will be posted tomorrow.

 

Multiple or Effective

The continuing and expanding challenges imposed on agronomic cropping systems by weed populations resistant to various herbicides has led to renewed interest in utilizing multiple modes of herbicide action in weed management programs. Indeed, articles written about and advertisements for products that contain multiple modes of action populate many farm media publications. But, simply because a herbicide premix or tankmix combination includes herbicides representing more than one mode of action doesn’t necessarily mean that each component in the premix or tankmix will be effective against the target weed species of greatest concern. There are many instances when multiple modes of action and effective modes of action are not synonymous. For example, two-component premixes of soil-applied herbicides containing a PPO inhibitor and ALS inhibitor do not contain two effective modes of action against ALS-resistant waterhemp. Tankmixtures or premixtures of glyphosate and dicamba do not contain two effective modes of action against glyphosate-resistant waterhemp.

 

Traits and timelines

Soybean varieties with traits conferring resistance to 2,4-D or dicamba have received USDA approvals for commercialization, but as of this writing neither trait has received approvals in certain export markets. Additionally, dicamba-containing products have not received federal or state labels for in-crop application in commercial soybean fields. Much interest exists about utilizing these new technologies to manage challenging weed populations, but uncertainty remains if these technologies will be broadly planted in 2016. Those who are planning to rely on these traits and technologies in their 2016 weed management programs are encouraged to develop contingency programs in the event these technologies are not broadly available in 2016.


Considerations for Weed Management in 2016

Here is the second installment with additional considerations for weed management in 2016.

Resistance remains

Herbicide-resistant weed populations continue to be a common occurrence across most areas of Illinois. Waterhemp and horseweed (marestail) are the two most common herbicide-resistant weed species in Illinois, and observations during 2015 suggest these species are likely to remain prevalent in 2016. Approximately 1700 waterhemp samples (representing 338 fields) were submitted to the University of Illinois Plant Clinic in 2015 for herbicide resistance screening. Although summary data for these samples are not yet available, the sheer number of samples submitted suggests herbicide-resistant waterhemp continues to be a significant management challenge for farmers. Waterhemp plants and/or populations resistant to herbicides from more than one site-of-action group are not uncommon, and we anticipate this phenomenon will continue. Data from 2014 indicated resistance occurred in close to 90% of the fields sampled, and multiple resistance to glyphosate and PPO inhibitors was confirmed in 52% of the fields sampled.

 

It’s not just the POST herbicides

Soil-applied PPO-inhibiting herbicides (sulfentrazone, flumioxazin, saflufenacil, etc.) can be effective against several small-seeded broadleaf weed species. These active ingredients are often selected to provide residual control of pigweed species in soybean, and frequently are applied with other active ingredients to broaden the weed-control spectrum. The foliar-applied PPO-inhibiting herbicides (lactofen, fomesafen, acifluorfen) constitute one site-of-action group for postemergence control of waterhemp and Palmer amaranth in soybean. As previously mentioned, resistance to PPO-inhibiting herbicides in waterhemp is becoming more common across Illinois. Some mistakenly believe this type of resistance is only to the foliar-applied PPO inhibitors, but resistance to PPO inhibitors occurs regardless of whether the herbicide is applied to the soil or to plant foliage. A more comprehensive article on this topic, first published in 2013, can be found at: http://bulletin.ipm.illinois.edu/?p=290

 


Considerations for Weed Management in 2016

One of the founding fathers of the United States is often credited as the source of the phrase “in this world nothing can be certain, except death and taxes.” Scholars and pundits alike have added other “certainties” to this relatively short original list, so perhaps we can enjoy a sense of serenity to suggest another: weeds. Even with all the time and resources expended to control weeds in 2015, one can be reasonably confident this persistent foe will again plague Illinois fields in 2016. As weed management practitioners begin to contemplate plans and programs for next season, a review of weed management in 2015 could provide a bit of sage counsel.  We will publish several short blogs over the next several days that both review 2015 and provide suggestions for 2016.

Challenges caused by weather

Weather patterns during portions of the 2015 growing season once again demonstrated the inherent perils of weed management programs that rely exclusively on one tool or tactic. These perils were often highlighted in soybean fields not treated with soil-residual herbicides. Applications of postemergence herbicides were often delayed by frequent precipitation and persistently wet field conditions until well beyond the point when weed interference began to reduce soybean yield. This provides a reminder of a very important central tenent of weed management: resources expended to keep weeds under control do not increase crop yield. Increases in crop yields are accomplished though plant breeding; weed management, on the other hand, preserves the genetic yield potential achieved through breeding. Put another way, weeds and crop plants require the same resources for growth. Any resource consumed by competing weeds becomes a resource unavailable for the crop to use to express its genetic yield potential. Once weed interference has persisted long enough to adversely impact crop yields, nothing can restore the lost yield.

Be cautious about which expenditures you trim

Lower commodity prices have many contemplating ways to reduce input costs in 2016. There are several viable options to reduce herbicide costs, but remember that hybrids and varieties, even those with the highest yield potential, will not realize their yield potential if weeds are not adequately and timely controlled. For example, assume a soybean farmer did not realize (or refuses to accept the fact) that glyphosate-resistant waterhemp infests a particular 60-acre field. The decision is made not to invest in an effective soil-residual herbicide; the farmer believes glyphosate alone will control the waterhemp. Following the in-crop application of glyphosate, two outcomes of this decision become rather obvious: poor control of waterhemp, and weed interference that continues to reduce soybean yield for much of the growing season. With a soybean yield potential of 65 bushels per acre, a modest yield loss of 20% due to weed interference, and a soybean market price of $9 per bushel, the decision to save a few dollars in weed control costs at the beginning of the season actually resulted in a revenue loss of over $100 per acre through reduced soybean yield. Keep in mind, especially while planning 2016 weed management programs, that wise investments to manage weeds before interference reduces crop yields will realize a return through more bushels harvested at the end of the growing season. An investment in high-yielding hybrids and varieties should be coupled with an investment in weed management that adequately protects yield potential.


Ewing Demonstration Center Fall Field Day – September 10th

The University of Illinois Extension will host its annual Ewing Demonstration Center Fall Field Day on Thursday, September 10, 2015 at 9:00 a.m.  The Ewing Demonstration Center is located in southern Illinois about 20 miles south of Mt. Vernon at 16132 N. Ewing Rd; Ewing, IL 62836.  It is on the north edge of the village of Ewing, north of the Ewing Grade School on north Ewing Road.  Watch for signs.

The ongoing research this year includes trials on soybean cover crops, nitrogen management in corn, corn maturity, corn seeding rates, soybean seed treatments, and a pumpkin variety trial.

 

The topics to be discussed at Field Day include:

 

Soybean Weed Management

  • Ron Krausz, Manager, SIU Belleville Research Center

2015 Cropping Season Challenges

  • Emerson Nafziger, Extension Crop Specialist, University of Illinois

Planning Ahead for the 2016 Wheat Crop

  • Robert Bellm, Extension Educator, University of Illinois

Results of 2015 Corn and Soybean Insect Surveys: Implications for 2016

  • Mike Gray, Extension Entomologist, University of Illinois

Making the Most of Prevent Plant Acres with Cover Crops

  • Nathan Johanning, Extension Educator, University of Illinois

 

The field day is free and open to anyone interested and lunch will be provided.  Certified Crop Advisor CEUs will also be offered (CM –  1.0, PM – 1.0, SW – 0.5).  For additional information, contact Nathan Johanning (618-687-1727; njohann@illinois.edu) or Marc Lamczyk (618-439-3178; lamczyk@illinois.edu).


The End of an Era

In early 1998, Extension specialists in the Department of Crop Sciences (Drs. Kevin Steffey, Mike Gray, Bob Hoeft, and Emerson Nafziger) launched a new educational program dubbed the Corn & Soybean Classic. The program consisted of a series of regional meetings at which extension specialists shared with those in attendance the most current and relevant information related to crop production, pest management, and farm economics. Annually for 18 years, 7 to 10 specialists spent many long hours compiling the information generated from applied and basic research programs into a format that was shared with an audience that ranged in size from 800 to over 1300. An estimate conducted during a recent Classic series suggested those attending that year represented approximately 8 million of Illinois’ agronomic crop producing acres.

The Classic changed and evolved over the years: several meeting venues around Illinois were tried; 29 different specialists from the University of Illinois spoke at one or more Classic meeting; leadership of the program began with Dr. Bob Hoeft, who upon becoming department head passed the mantel of leadership to Dr. Kevin Steffey, who upon his retirement from the University of Illinois passed it along to me. Sharon Conatser and Kris Ritter provided the behind-the-scenes support for the program during its early years, which later transitioned to Sandy Osterbur who became coordinator of the program. Even with these and the numerous other changes that occurred over the years, the individuals involved with putting together the program always remained committed to providing a research-based program that was the best possible.

The adage that all good things must come to an end now also applies to the Corn & Soybean Classic; the 2015 program was the last. As extension faculty retire or move on from the University of Illinois, their positions are not being refilled with tenure-track extension faculty. Those few of us who remain feel that we can no longer maintain the standard of excellence that was the hallmark of the Classic. We currently are exploring alternative formats for conveying our research results and recommendations, but to date have not reached any decisions.

Similar challenges have led to changes in another of our programs, the University of Illinois AGMasters. Recently, we partnered with the Illinois Certified Crop Advisor (CCA) program to transition the AGMasters to a one-day format that will be held in Springfield on December 3, the day following the annual CCA conference. We sincerely appreciate the Illinois CCA program’s willingness to assist us with this educational program.

On behalf of my colleagues, thank you for your support of the University of Illinois Corn & Soybean Classic and AGMasters.


Brownstown Agronomy Research Center Field Day – August 5, 2015

The 2015 Brownstown Agronomy Research Center Field Day, presented by the University Of Illinois Department Of Crop Sciences, will be held on Wednesday, August 5. Extension researchers and specialists will address issues pertinent to the current growing season. The tour will start at 8 a.m. and will last approximately three hours. It will be followed by lunch provided by U of I Extension. 2.5 hours of Certified Crop Adviser CEUs have been approved.

Shaded tour wagons will take participants to each stop. These topics will be addressed:

  • 2015 Cropping Season Challenges – Dr. Emerson Nafziger, U of I
  • Weed Management: The Simple Days are Over – Dr. Aaron Hager, U of I
  • Soybean Sudden Death Syndrome – Dr. Angie Peltier, U of I
  • Update on Statewide Insect Surveys & Potential Implications – Dr. Mike Gray, U of I
  • Factors Contributing to a Healthy Soil – Russ Higgins, U of I

The 208-acre Brownstown Agronomy Research Center has been conducting crop research on the claypan soils of southern Illinois since 1937. More than 30 research and demonstration projects are conducted at the Center each year. Visitors are always welcome.

The research center is located south of Brownstown on IL Route 185, approximately 4 miles east of the IL Route 40/185 junction.

For more information, contact Robert Bellm (618-427-3349); rcbellm@illinois.edu
Visit us on the web at http://web.extension.illinois.edu/barc/


Reminder…Weed Science Field Research Tour

The 2015 University of Illinois Weed Science Field Day will be held next Wednesday, June 24th at the University of Illinois Crop Sciences Research and Education Center, located immediately south of the main campus. Coffee and refreshments will be available under the shade trees near the Seed House beginning at 8:00 a.m.

Similar to past years, we will car pool to the fields where participants can join in a guided (but informal) tour format. The tour will provide ample opportunity to look at research plots and interact with weed science faculty, staff, and graduate students. Participants can compare their favorite corn and soybean herbicide programs to other commercial programs and get an early look a few new products that soon will be on the market. The tour will conclude around noon with a catered lunch at the Seed House.

Cost for the Urbana weed science field tour is $10, which will help defray the cost of the field tour book, refreshments and lunch. We will apply for 2 hours of CCA credit under the IPM category.


International Agronomy Day

The Department of Crop Sciences will host International Agronomy Day on August 31, 2015 at the Crop Sciences Research and Education Center at the University of Illinois. We have developed International Agronomy Day as an opportunity for international visitors to attend a field tour at the University of Illinois and interact with many of our faculty and staff.  International Agronomy Day will take place the day before the Farm Progress Show opens in Decatur to provide an opportunity for international visitors traveling to the United States to attend the Farm Progress Show to learn more about the research being conducted by our faculty and staff. Advanced registration is required to attend International Agronomy Day. More information about the program is available at http://internationalagronomyday.org/ Information in Spanish is available at http://spanish.internationalagronomyday.org/


Identification of Palmer amaranth in Illinois

Palmer amaranth continued to expand its presence in Illinois during 2014. Palmer amaranth populations have been confirmed in counties colored orange or blue in Figure 1; orange designates glyphosate-resistant populations are present in these counties. It should be neither construed nor assumed that Palmer amaranth populations occur only in the counties colored on this map. It is altogether likely that Palmer amaranth populations are present in many other counties. Emerged Palmer amaranth plants were observed on May 7 at our field research location west of Kankakee.

Palmer amaranth distribution May 2015

Once again, we will assist Illinois weed management practitioners in accurately identifying Palmer amaranth. We will accept tissue samples from suspected Palmer amaranth plants and use tools of molecular biology to identify whether the sample is Palmer amaranth or another species of Amaranthus. Information on how to collect and submit tissue samples from suspected Palmer amaranth plants can be found in the “Palmer Amaranth Identification” form that accompanies this article. Please download this form, provide as much information as possible, and submit it along with the tissue samples to the address listed at the top of the form.

Also, please note that screening for herbicide resistance in waterhemp is now a service offered by the University of Illinois Plant Clinic and requires a different sample submission form.  More details about sample submission for herbicide resistance screening is available at: http://bulletin.ipm.illinois.edu/?p=3224

Palmer Amaranth Identification