C.O.R.N. Newsletter 2012-03

Dates Covered: 
February 7, 2012 - February 21, 2012
Editor: 
Harold Watters

New Bt Corn Hybrids and Resistance Issues

There have been new products added to the list of those containing Bt proteins for control of above and below ground insects.  From Monsanto, there is Genuity VT Double Pro RIB Complete with Cry1A.105 and Cry2Ab2 for above ground insects, a product that is RIB, or refuge in the bag.  These are the same genes in Genuity VT Double Pro (VT2P) but the refuge is now mixed within the bag at the 5% level.  New products from Pioneer include Optimum Intrasect Xtra which contains Cry1F and Cry1Ab for above ground and Cry34/35Ab1 for below ground insects, and Optimum TRIsect which contains Cry1F and mCry3A, the first time that these two genes are together, also for above and below ground insects.  Both of these products require a 20% refuge.

On another issue, we just attended meetings where rootworm resistance to the Cry3Bb1 gene that was discovered in the central Midwest was discussed among researchers, extension specialists, and the various seed companies.  So far, resistance has not been seen with any of the other gene proteins.  Of primary concern was how to handle corn plantings in future years in those areas where resistance developed.  Resistance has NOT been found in Ohio rootworm populations.  However, of importance to Ohio growers is to remind them of the continued potential for resistance to develop, and what we need to do to help prevent it from occurring in our state. 

As discussed last August in the C.O.R.N. 2011-26 issue, growers should

1) rotate to another crop such as soybean (albeit keeping an eye out for the western corn rootworm variant),

2) ALWAYS PLANT THE REFUGE (remember that this is a requirement, which will automatically be planted if you use an RIB, or refuge in the bag, product),

3) if deciding to plant continuous corn, rotate among other rootworm management tactics such as using a soil insecticide, and

4) if wanting to continue to plant a rootworm Bt hybrid to control rootworm larvae, use a pyramided gene product such as SmartStax or rotate to a single gene product not containing the Cry3Bb1 gene. 

It is to all our benefit if growers employ practices that will help to prevent resistance from becoming an Ohio problem!

Converting pounds per acre to parts per million on soil test report

The focus of soil fertility and management for crop production is traditionally the tilled layer of the soil which goes back to the days when a plow was the main tillage implement on the farm. This 6-8 inch layer of soil is known as the plow layer. Interestingly a plow layer weighs approximately 2 million pounds. In more recent years soil test labs have moved away from reporting soil test results in pounds per acre but instead as parts per million (ppm). Due to the relationship between the plow layers weight being 2 million pounds we can readily convert using a factor 2. A soil reported as 25 ppm has a pound per acre soil test level of 50 pounds per acre (25 ppm times 2=50 pounds per acre). To convert 40 pounds per acre to ppm we just divide 40 pounds per acre by 2 to equal 20 ppm (40 pounds per acre/2= 20 ppm). This conversion works for all nutrients reported including phosphorous, potassium, calcium or magnesium as well as any other nutrient reported in these units.

 

Updated Fertilizer Recommendation Charts from the Tri-State Fertilizer Recommendations for Phosphorous

Fertilizer recommendations for corn (Table 1), soybeans (Table 2) and wheat (Table 3) are listed below. The tables are updated to reflect the higher yield potentials utilizing the equations from the Tri State Fertilizer Recommendations publication can be found at: http://ohioline.osu.edu/e2567/index.html. The philosophy of these recommendations can be found in the original publication.

Table 1. Fertilizer P Recommendations for Corn. (adapted from Tri-state Fertilizer Recommendations for Corn, Soybeans, Wheat and Alfalfa)

 

Realistic Yield Goal (bu/acre)

Soil Test Level

120

145

170

200

225

250

275

PPM (lb/acre)

lbs P2O5/acre recommended

5 (10)

95

105

115

125

135

145

155

10 (20)

70

80

90

100

110

120

125

15-30 (30-60)

45

55

65

75

85

95

100

35 (70)

20

25

30

40

45

50

50

40 (80)

0

0

0

0

0

0

0

 

 

 

 

 

 

 

 

 

 

 

Table 2. Fertilizer P Recommendations for Soybean. (adapted from Tri-state Fertilizer Recommendations for Corn, Soybeans, Wheat and Alfalfa)

 

Realistic Yield Goal (bu/acre)

 

Soil Test Level

30

40

50

60

70

80

90

PPM (lb/acre)

lbs P2O5/acre recommended

5 (10)

75

80

90

100

105

115

125

10 (20)

50

55

65

75

80

90

100

15-30 (30-60)

25

30

40

50

55

65

70

35 (70)

10

15

25

25

30

35

35

40 (80)

0

0

0

0

0

0

0

 

 

 

 

 

 

 

 

 

 

Table 3. Fertilizer P Recommendations for Wheat. (adapted from Tri-state Fertilizer Recommendations for Corn, Soybeans, Wheat and Alfalfa)

 

Realistic Yield Goal (bu/acre)

Soil Test Level

50

65

80

95

110

125

PPM (lb/acre)

lbs P2O5/acre recommended

15 (30)

80

90

100

110

120

130

20 (40)

55

65

75

85

95

105

25-40 (50-80)

30

40

50

60

70

80

45 (90)

15

20

25

30

35

40

50 (100)

0

0

0

0

0

0

 

 

Strategies for spring marestail management

OSU research on marestail management has shown that a systems approach, involving a combination of herbicide applications, provides the most consistently effective control and reduction in marestail population over time.  Given that essentially all of the marestail populations in the state are glyphosate-resistant by now, and something like 25% of these are also resistant to ALS inhibitors (Classic, FirstRate), POST applications are often the least important application in a marestail control program.  The exception to this is LibertyLink soybeans of course, where the POST Liberty application has considerable value when preceded by an appropriate preplant burndown/residual treatment.  In Roundup Ready soybeans, we have obtained the most consistently effective control with a combination of fall and spring preplant treatments, where the fall treatment contains a low rate of Canopy EX/DF that has some residual control, and the spring treatment contains effective burndown herbicides along with the majority of the residual herbicide (e.g. Valor XLT, Sonic, Authority First, etc).  Use of even non-residual herbicides in the fall seems to improve the effectiveness of spring treatments, although not in every situation, whereas failure to apply in fall introduces more variability in control.  This is the situation we find ourselves in coming into this spring though, due to the lack of time and good weather last fall to get herbicide applied. 

It is possible to obtain adequate control of marestail with a single spring application, but there is some inherent variability with this approach.  It can also be difficult to determine an optimum time for application.  There is a tradeoff that occurs with early versus late spring applications in that applying early in spring (late March/early April) makes control of emerged plants more consistent, but can result in the residual herbicide activity not persisting into early summer when marestail are still emerging.  Applying later in spring (late April/early May) can reduce the risk of the residual running out too early, but increases the risk of ineffective burndown of emerged plants, especially where there was no fall application and overwintered plants are present.  With regard to minimizing soybean yield loss and marestail seed production, ensuring a weedfree start at planting is more important than ensuring near 100% control of later-emerging plants.  As we found out last year in a very wet spring, waiting too long to apply burndown herbicides can result in major control problems.   

The bottom line here is that there is no one easy approach to marestail management that consistently optimizes both burndown and residual control of marestail.  Several possible approaches are offered for your consideration here, with the caveat that any of them may work in a field with a low infestation level and the growing season progresses “normally”, but the more complex approach will help ensure control when populations are higher and the growing season less favorable.  

Approach 1.  Application of burndown plus residual herbicides in early spring (late March/early April).  This accomplishes the goal of applying early enough to ensure that burndown of emerged plants is not an issue.  We have had consistent results with 2,4-D applied this early for marestail control.  Applying all of the residual herbicide at this time can result in late-emerging marestail escapes in late May or early June if the residual herbicide activity runs out by then.  Keys to making this approach work:  1) increase the residual herbicide rate, especially of the non-ALS component (Valor, Authority, metribuzin) or add another broadleaf herbicide with marestail activity; and 2) scout the field prior to soybean emergence and apply Liberty + metribuzin, Sharpen + glyphosate, or Gramoxone + metribuzin if small marestail are observed then. 

Approach 2.  Application of burndown plus residual herbicides in late April or close to planting (whenever that is).  This accomplishes the goal of applying the residual later in the season, which increases the potential for adequate control of late-emerging marestail plants.  The disadvantage of waiting this late, especially as applications are delayed into May, is increased variability in the burndown of existing plants.  This variability can be minimized by increasing burndown herbicide rates or by using a more effective mix of burndown herbicides.  Some examples:  1) rates of Liberty can be increased from 29 to 36 oz/A as the season progresses, along with the addition of a few ounces of metribuzin; and 2) the three-way combination of Sharpen + glyphosate + 2,4-D ester may be more consistently effective than glyphosate + 2,4-D.  Be cautious about the effectiveness of glyphosate plus 2,4-D alone once marestail plants have started stem elongation.

Approach 3.  Split preplant/preemergence application of herbicides.  This can take various forms, but in our thinking would most likely be something like the following:  A) late March/early April application of glyphosate + 2,4-D + a low rate of residual herbicide (several ounces of metribuzin or a low rate of Canopy DF); followed by B) a second application at the time of soybean planting consisting of the majority of the residual herbicide (Valor XLT, Gangster, Sonic, etc) plus whatever additional burndown is needed.  Need for additional burndown could be minimal with a late-April planting, but fields should be scouted to determine this, and burndown adjusted accordingly.  It would also be possible to use products such as Valor XLT, Envive, Authority XL, etc, applying half the total rate in early March/late April, and the rest at the time of planting.  The obvious drawbacks of this approach compared with the single-application approaches are increased cost and time, and soil conditions in early spring may be unsuitable for traffic.  The primary benefit is more consistent control of marestail across a range of marestail population densities and emergence patterns, weather conditions, and planting dates.  By making two applications, there is flexibility built into the second application that should reduce the chances of a significant in-season marestail problem. 

There is of course a continuum between approaches 1 and 2, since preplant applications can conceivably be made anytime between late March and when soybeans are finally planted.  Application timing is dependent upon weather and soil conditions as well.   The main things to keep in mind are that burndown of marestail becomes more variable as we move from early to late April and beyond, while applying later improves chances that residual herbicides will control marestail that emerge in late May and June.  Consult Table 13 in the current “Weed Control Guide for Ohio and Indiana” for information on residual herbicide effectiveness.   Best results occur by using herbicides that are rated an 8 or higher in the “ALS-resistant” marestail column. 

More information on marestail management can be found in OSU Extension Bulleting 789, “Weed Control Guide for Ohio and Indiana” and the OSU/Purdue fact sheet, “Control of Marestail in No-till Soybeans”.  These are available at OSU Extension County offices and online at: https://agcrops.osu.edu/specialists/weeds.   We should also have a short video posted on this subject within a day or so.

 

Farm Science Review Celebrates 50 Years of Innovation, Conservation, and Demonstrations

As the Farm Science Review looks forward to its 50th show September 18-20 2012, show organizers want to get in contact with individuals who were in attendance at the early Reviews dating back as far as 1963 when it was held at Ohio State’s Don Scott field in Columbus. In particular, we are interested in finding:

·      People who have attended every Review

·      People who attended the very first Review

·      Innovations adopted after their introduction at the Farm Science Review

·      Family memories that involve the Farm Science Review

·      Multi-generational stories of Farm Science Review

Please submit information along with contact information, memories, or digital copies of photos to lindsay@wiltpr.com

For more information about Farm Science Review, visit http://fsr.osu.edu

 

Applying Liquid Manure to Wheat and Corn Meeting Planned

Livestock producers and grain farmers interested in learning about utilizing liquid swine and dairy manure on wheat and corn should plan on attending a program at the Putnam County Extension office on Thursday, March 1st at 7:00pm. The Putnam County Extension Office address is 124 Putnam Parkway, Ottawa Ohio 45875.

Glen Arnold, OSU Extension Field Specialist, Manure Nutrient Management Systems will be presenting on-farm research plot results from recent years including the 2011 crop season.

Top-dressing wheat in April (after the wheat has broken winter dormancy) using swine manure has worked well for producers using this application window. Liquid swine manure can contain from 30 to 55 pounds of ammonia nitrogen per 1,000 gallons. Applying manure as a spring topdress to wheat has produced yields similar to or better than purchased fertilizer when fields are firm enough to support the application equipment.

Side-dressing corn with swine and dairy manure has also proven to be an effective use of manure nutrients while saving the cost of purchased fertilizer. Applying manure to a growing crop also allows for better utilization of the manure nutrients, especially the nitrogen and phosphorus portions. Swine finishing manure applied as a side-dress to meet corn nitrogen needs also supplies enough phosphorus and most of the potash needed for a soybean crop the following season.

The application of manure to fields that have not traditionally received manure has resulted in improved test weights in wheat and corn harvested. While more research is needed to confirm these preliminary findings the results do look promising for grain farmers interested in having manure applied to their fields from livestock operations.

An additional topic will be discussing the modifications made to a 5,200 gallon manure tanker to adapt it for row crop manure application on corn. Modifications included replacing the 30” tires with 18” tires on offset rims, adjusting the toolbar to incorporate manure in standing corn, and calibrating the tanker for applying the correct amount of manure.

Registration cost for the program is $10 in advance or $15 at the door. Checks can be made payable to OSU Extension and mailed to the Hancock County Extension office, 7868 CR 140, Suite B, Findlay Ohio 45840. For a flyer that includes a registration form click here http://putnam.osu.edu/events/applying-liquid-livestock-manure

 

Certified Crop Advisor and Certified Livestock Manager credits for this meeting have been applied for.

MPNAA Meeting Reminder

The registration deadline for the Winter Meeting of the Midwest Professional Nutrient Applicators Association is February 22. RSVP here: http://oema.osu.edu/mpnaa.html

February 2012 AgCrops Calendar

February 2012 - for complete details see: https://agcrops.osu.edu/calendar

February 14

2012 Conservation Tillage Breakfast Meetings- 4 of 5

Plaza Inn, Mt. Victory

Program is Management of Hard to Control Weeds (like Marestail) Dr. Steve Prochaska, Crawford County Extension Educator.

February 14

Soybean Workshop

Northwest Agricultural Research Station, 4240 Range Line Road, Custar, Ohio

Soybean populations, cover crops, cultural practices and disease will be the highlighted during this intensive session.

February 15

Ohio Pesticide Commercial Applicator Recertification Conferences 2012

Dayton Convention Center, Dayton, Ohio

Recertification opportunity for Ohio Commercial license holders.

February 21

Software for Developing Nutrient Management Plans Workshop

Marion County Extension Office, 222 West Center Street, Marion, Ohio 43302

For Certified Crop Advisers who would like to become a NRCS Certified Nutrient Management Plan Provider Planner

February 28

2012 Conservation Tillage Breakfast Meetings- 5 of 5

Plaza Inn, Mt. Victory

Program is Current and Future Uses For Precision Agriculture Dr. Scott Shearer, OSU, Chairman of Dept. of Food, Agriculture and Biological Engineering.

February 28

Weed Resistance Workshops

Ohio Agricultural Research & Development Center, 1680 Madison Avenue, Wooster, OH

Highlight weed resistance issues in Ohio and offer proposed solutions • Make predictions for future weed resistance issues and management • Provide recommendations for ways to mitigate resistance using technology and Round-up Ready seed varieties

February 29

Midwest Professional Nutrient Applicators Association Winter Meeting

Shawnee Prairie Preserve Nature Center and Park Offices 4267 State Route 502 W Greenville, OH

6 CLM Credits and 2 IN CCH available, IN PARP credits applied for. (PARP– bring permit # and $10 to cover fee). Registration Deadline: February 22 Registration: $25

February 29

Weed Resistance Workshops

The Fawcett Center 2400 Olentangy River Rd., Columbus, Ohio

Highlight weed resistance issues in Ohio and offer proposed solutions • Make predictions for future weed resistance issues and management • Provide recommendations for ways to mitigate resistance using technology and Round-up Ready seed varieties.

Archive Issue Contributors: 
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About the C.O.R.N. Newsletter

C.O.R.N. Newsletter is a summary of crop observations, related information, and appropriate recommendations for Ohio crop producers and industry. C.O.R.N. Newsletter is produced by the Ohio State University Extension Agronomy Team, state specialists at The Ohio State University and the Ohio Agricultural Research and Development Center (OARDC). C.O.R.N. Newsletter questions are directed to Extension and OARDC state specialists and associates at Ohio State.