C.O.R.N. Newsletter 2011-27

Dates Covered: 
August 16, 2011 - August 23, 2011
Editor: 
Rob Leeds
Fields Being Sprayed for Soybean Aphids

Fields Being Sprayed for Soybean Aphids

We received our first reports of soybean aphids being treated in northwest Ohio, with levels in most fields, while not being at threshold, are noticeable and rising.  Growers throughout the state, especially in the north, should consider scouting their fields for the remainder of the summer.   We suggest scouting throughout the state because in 2009, the last year that we had aphids, we saw large populations in southern Ohio.  While we cannot predict whether any area or field will have populations reaching threshold, the possibility exists.

Remember that the threshold for spraying is an average of 250 aphids per plant with a rising population (http://ohioline.osu.edu/ent-fact/pdf/0037.pdf ).  This is the threshold for taking action, not the economic injury levels which is in the vicinity of 700-900 aphids per plant.  So there is no need to spray prior to an average of 250 aphids per plant.  However, in past years we have mentioned the existence of a sampling procedure called speed scouting that was developed at the University of Minnesota.  This method suggests that when most of the plants have over 40 aphids per plant (e.g., 11 of 11 randomly sampled plants all have over 40 aphids per plant without any plants having below that number), treatment is warranted.  In speed scouting, it is suggested that you should sample twice within 3-4 days, making a treatment decision each time, before actually making the choice to treat.  For more information on soybean aphid speed scouting, see the following two web sites out of Iowa State University for a speed scouting brochure and video, respectively: http://www.iasoybeans.com/productionresearch/publications/aphidcard/aphidcard.pdf and   http://www.plantmanagementnetwork.org/edcenter/seminars/AphidSpeedScouting/ .

We also remind growers that in dry areas of the state, twospotted spider mites are still being found and should be watched closely.  In addition, the various soybean defoliators that occur each summer are being found and warrant watching, including Japanese beetles, Mexican beetles, bean leaf beetles, and grasshoppers.  See our web site at http://entomology.osu.edu/ag/ for information on all of these pests.  Finally, please remember guidelines for protecting honeybees when applying insecticides to soybean.  According to Ohio law, if a pesticide is toxic to bees, it is the applicator’s responsibility to contact the beekeepers with registered apiaries (beehives) within ½ mile of the target area if it is more than ½ acre in size and the crop is in flower.  Contact the Ohio Department of Agriculture for more information on apiaries in your area.

Cooler nights during grain fill beneficial for corn

During the past two weeks, we have received a break from daily highs above 90 degrees F. The drop in temperatures, especially the lower night time temperatures, can be beneficial for corn. Crop physiologists believe that high night temperatures (in the 70s or 80s ) can result in wasteful respiration and a lower net amount of dry matter accumulation in plants. The rate of respiration of plants increases rapidly as the temperature increases, approximately doubling for each 13 degree F increase. With high night temperatures more of the sugars produced by photosynthesis during the day are lost; less is available to fill developing kernels, thereby lowering potential grain yield. High night time temperatures result in faster heat unit (GDD) accumulation that can lead to earlier corn maturation, whereas cool night temperatures result in slower GDD accumulation that can lengthen grain filling and promote greater dry matter accumulation and grain yields.

 Past research at the University of Illinois indicates that corn grown at night temperatures in the mid-60s outyields corn grown at temperatures in the mid-80s. Corn yields are often higher with irrigation in western states, which have low humidity and limited rainfall. While these areas are characterized by hot sunny days, night temperatures are often cooler than in the Eastern Corn Belt.  Low night temperatures during grain fill have been associated with some of Ohio’s highest corn yields in past years. In 2009, when the highest state average yield to date was achieved (174 bu/A), Ohio experienced one of its coolest Julys on record. The cool night temperatures may have reduced respiration losses during early grain fill and lengthened the grain fill period.

Wheat Variety Yield in 15 Inch Rows

What will 15 inch row wheat yield?  Because some Ohio wheat producers are interested in growing soft red winter wheat in 15-inch rows in order to utilize a more precise planting implement, reduce equipment inventory, Modify Relay Intercrop (MRI) soybeans into wheat (done when wheat is headed out), sow cover crops or establish a forage crop; wheat yield in a 15 inch row is important in evaluating any row spacing change.  

Research done by Beuerlein & Minyo in 2008 with 3 wheat trials found 7.5 inch row spacing to out yield 15 inch row spacing  by  about  7.2 % or 6.6 bushels per acre (bu/ac). To read this research report, go to:  http://corn.osu.edu/newsletters/2010/2010-24/effect-of-wheat-growth-habit-seeding-rate-and-row-spacing-on-yield?searchterm=wheat+yield+in+15+inch+rows.

In 2009 and 2010, Lee and Herbek, of the University of Kentucky,  grew three varieties of wheat at two locations in 15-inch and 7.5-inch rows. Varieties tested were known to be prolific (varieties produce a lot of tillers). Yields ranged from 70 to just over 120 bu/ac. In two of the environments, there were not any differences in yield between 15-inch and 7.5-inch rows. In the other two environments, wheat yields in 15-inch rows were about 8.5% less than wheat yields in 7.5-inch rows. To read the entire research summary go to http://www2.ca.uky.edu/wheatscience-files/Lee_-_Wheat_Yield_in_15_Rows_RR_09-10.pdf.

 Johnson, in 2006 and 2007, examined wheat yield in 7.5 and 15 inch row wheat in Ontario.  Wheat yields were reduced from 5 to 8 percent when wheat rows were widened.  For more information on this trial, go to http://www.ontariosoilcrop.org/docs/V4Cer6.pdf.  

In 2011, Minyo evaluated wheat varieties in a 15 inch row spacing over yield at the Bucyrus location of the Ohio Wheat Performance Test.  Varieties selected were in the top half of the 2010 Ohio Wheat Performance Test. The average yield for this plot of 25 varieties was 93.2 bu/ac with a range from 88.1 to 99.8 bu/ac.  Seeding rate was 25 seeds per foot of row for all varieties.

All of the wheat varieties in the 15 inch row trial were also in the 2011 - 7.5 inch row trial at Bucyrus (70 varieties tested) which averaged 98.3 bu/ac with a range of 107.4 to 82.1 bu/ac .  It should be noted that a statistical comparison between the two wheat row spacing’s cannot be made from the 2011 study at Bucyrus.  Therefore, only relative yield of wheat in 15 inch rows by variety is reported in the linked table.  A further limitation of this data is that it represents only one location and one year. The Ohio Wheat Performance Test is available at http://www.oardc.ohio-state.edu/wheattrials/.

If farmers wish to MRI, double crop or sow a forage/cover crop into the wheat, then in addition to yield in a 15 inch row, maturity and plant growth habit (reported in another article at http://crawford.osu.edu  are very important to the establishment and growth of the subsequent crop from the aspect of available light.  For example soybeans interseeded into wheat with a dense canopy (>3 on scale used by Beuerlein and Minyo )  and prior to head emergence may  become spindly and may  be of low vigor.  Light available for the interseeded crop will be a function of heading date (maturity), plant growth habit, row spacing and yield.

2011 WHEAT PERFORMANCE

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Wide Row (15") Variety Evaluation Crawford County

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Seed

Spring

Head

LG

Yield

Moist

TW

Brand

Cultivar

Ft./Row

Stand

Date

%

bu/ac

%

lb/bu

AGI

206B

25

100

144

0

94.8

13.5

60.7

Beck

113

25

100

144

0

91.5

13.2

60.0

Beck

135

25

100

145

0

99.8

14.4

59.3

Direct Enterprises

Sienna

25

100

145

0

98.5

12.5

59.9

Dyna-Gro

9042

25

100

144

0

93.8

12.5

59.5

Dyna-Gro

9053

25

100

146

0

93.0

11.5

57.8

Dyna-Gro

9922

25

100

144

0

93.9

14.2

58.6

Ebberts

590

25

100

143

4

94.4

14.2

62.4

Ebberts

634

25

100

145

5

89.4

12.9

60.4

Excel

234

25

100

144

5

93.4

13.6

60.5

Pro. Certified

Sunburst

25

100

146

0

88.7

14.4

60.7

Rupp

RS 934

25

100

144

3

93.2

14.0

62.5

Rupp

RS 978

25

100

142

5

88.4

12.3

59.4

Seed Consultants

SC 1321

25

100

144

0

97.5

12.4

58.0

Seed Consultants

SC 1341

25

100

145

0

88.2

11.1

57.1

Shur Grow

SG-1549

25

100

144

3

92.5

14.0

62.6

Steyer

Ashlyn

25

100

144

0

91.5

13.9

60.0

Steyer

Jordan

25

100

144

1

91.2

14.2

62.4

Steyer

Marion

25

100

144

0

96.3

12.6

59.5

Strike

936

25

100

144

0

92.6

12.7

57.5

Strike

937

25

100

144

0

91.3

12.6

59.3

Syngenta

W1104

25

100

146

0

97.9

13.3

59.9

Syngenta

W1377

25

100

145

3

88.1

14.1

62.7

Wellman

W 123

25

100

143

3

94.2

11.9

57.7

Wellman

W 132

25

100

143

5

94.6

12.2

59.4

 

 

 

 

 

 

 

 

 

High

 

25

100

146

5

99.8

14.4

62.7

Average

 

25

100

144

1

93.2

13.1

59.9

Low

 

25

100

142

0

88.1

11.1

57.1

LSD (P=0.3)

 

 

 

0.4

1.0

2.0

0.3

0.4

CV

 

 

 

0.4

98.0

2.9

3.0

0.9

Organic Soybean Pest Management Field Day

Organic Soybean Pest Management Field Day to be held August 17 from 12:00 - 3:00 pm.

Location: 13737 Middleton Pike road (St. Rt. 582) at the Ag Incubator Foundation which is ½ mile west of St. Rt. 25 on st. Rt. 582, north of Bowling Green.

Speaker: Dr. Andy Michel, Entomologist, Ohio State University Extension

Agenda: Farming Systems experiment - certified organic soybeans, reduced input and notill conventional production.

Insect pests of soybeans - how to identify, trapping and scouting, control measures

Northwest Ohio Cooperative kitchen shared use facility for canning and freezing

Free to the public. No registration needed. Free local foods lunch provided. Call 419-354-9050 for more information.

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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.