Iowa State University Extension and Outreach

East-Central and Southeast Iowa Crop Information

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May 20, 2011

 

CORN

 

Black Cutworm

 

Black cutworms have started feeding in southern Iowa, essentially south of Highway 92. Erin Hodgson has received many reports on black cutworm damage, with cutting exceeding 3% in some cases. Based on temperatures, since the first significant flights of Black Cutworm moths into Iowa, and using National Weather Service forecasts through May 22, cutting in eastern Iowa, if it occurs, should have begun along Highway 34 on Wednesday, May 18 and should begin along Interstate 80 on Friday, May 20, along Highway 30 on Saturday, May 21, and along Highway 20 on Monday, May 23. It is always good to start scouting a few days before the predicted onset of cutting.

Of course, any changes in predicted temperatures may alter the onset of any cutting. You can monitor black cutworm growing degree days for east-central and southeast Iowa at http://www.extension.iastate.edu/Pages/eccrops/blackcutworm.html. A more comprehensive overview of the 2011 black cutworm situation is posted at http://www.extension.iastate.edu/CropNews/2011/0505sisson.htm.

Also, remember that, with high priced corn, the damage threshold for treatment is lower. An excellent tool is the dynamic black cutworm action threshold, which is an Excel spreadsheet. A description of this tool and a link to download it are at http://www.extension.iastate.edu/CropNews/2009/0527hodgson.htm. This spreadsheet takes into account your starting stand, corn yield potential, cost of control, and market value of corn. In short, if you don’t have any corn population to spare (start at 30,000), have a 200 bu/A potential, think you can get $7/bu, and the cost of control is around $15/A, the threshold for treatment is 1% cut plants, rather than the standard 2-3% cutting.

There are many products labeled for black cutworm control in corn, including:

 

Insecticide

Rate

Ambush

6.4-12.8 oz/acre

Asana XL

5.8-9.6 oz/acre

Baythroid XL

0.8-1.6 oz/acre

Capture 1.15G

0.04-0.10 lb/acre

Discipline 2EC

2.1-6.4 oz/acre

Lorsban 4E

1-2 pt/acre

Mustang Max

1.28-2.8 oz/acre

Nufos 4E

1-2 pt/acre

Penncap-M

4 pt/acre

Pounce 25 WP

6.4-9.6 oz/acre

Sevin XLR Plus

2 qt/acre

Warrior II

0.96-1.6 oz/acre

 

SOYBEANS

 

Fields With Damping Off Needed For Research

 

Hopefully the delay in soybean planting will help to reduce some soybean disease problems, including sudden death syndrome. However, the cooler than normal soil temperatures of the last week may increase chances for some seedling diseases. Alison Robertson is looking for soybean fields that have a problem with damping off. If you know of any fields with stand problems that are showing signs of damping off, Alison would like to collect a few plants from the field. You can contact her at alisonr@iastate.edu or 515-294-6708. For more information see http://www.extension.iastate.edu/CropNews/2011/0511robertson.htm.

 

Checking Soybean Stands

 

One thing to keep in mind when checking soybean stands is that many still plant soybeans thicker than what is needed for optimum yields. A final stand of a uniform 100,000 plants per acre should maximize yields, and it seldom pays to replant stands of 70,000-75,000, because of the cost of replanting and yield penalty for the delayed planting. It takes about 5 plants per foot of row in 36-38" rows, 4 plants per foot in 30" rows,  3 plants per foot in 20" rows and 2 plants per foot in 15" rows to equal about 70,000-75,000 plants per acre. For drilled beans it is easier to use a hoop to take stand counts. It takes 10 plants per hoop with a 33" diameter hoop, and 12 plants per hoop with a 36" diameter hoop to equal about 70,000-75,000 plants/A.

 


FOR YOUR CALENDAR

 

IOWA LEARNING FARM COVER CROPS FIELD DAY

ROB STOUT FARM – WASHINGTON COUNTY - 2449 HEMLOCK AVE

2.5 MILES SOUTH OF WEST CHESTER

JUNE 1 5:30 PM – 7:30 PM

FREE MEAL

 

        See and Hear about Rob’s and Other Area Farmer’s Experiences with Fall Cover Crops.

        See the Iowa Learning Farm’s Conservation Station Mobile Lab

        Discuss Cover Crop Issues With USDA, Iowa Learning Farm, and ISU Experts

 

 

SPRING FIELD DAY & SPECIAL SESSION FOR CCAs

SE IA RESEARCH FARM – CRAWFORDSVILLE

JUNE 15

 

 Certified Crop Advisors can obtain 5 hours of credit (including 3 hours in soil and water management) by attending a special session  in the morning followed by the afternoon tour at the ISU SE Iowa Research & Demonstration Farm near Crawfordsville on June 15. There is a $50 fee ($70 after June 13) for CCAs attending for credit (includes lunch). There is no charge for the afternoon field day except a $7 fee for those wanting lunch at noon. Fees (check or cash) can be paid at the door, but if you plan to attend the morning session or want to reserve a lunch at noon, please send me (fawcett@iastate.edu) a note by June 13.

 

Special Session for Certified Crop Advisors

(0.5 hour pest management, 2.5 soil & water management)

 

9:00 a.m.      Recent Tile Drainage Research Results & 20 Years of Conservation Tillage Research

Greg Brenneman, ISU Extension Ag Engineer

 

10:00 a.m.   Nematodes that Feed on Corn – Biology & Control

Greg Tylka, ISU Extension Plant Pathologist

 

10:30 a.m.   Everything You Ever Wanted to Know About Cover Crops But Were Afraid to Ask

Jeremy Singer, National Laboratory for Agriculture and the Environment

 

Noon                           Lunch

 

1:00 p.m. – 3:00 p.m. Spring Field Day Tour

(1.0 hour pest management, 0.5 hour soil & water, 0.5 hour crop management)

 

Tour Stops:

 

Crop Season Review & Making Marketing Decisions

Kevin Van Dee, Farm Superintendent &

Jim Jensen, ISU Extension Farm Management Specialist

 

Cover Crop Establishment & Management

Jeremy Singer, National Laboratory for Agriculture and the Environment

 

Corn Nematode Management

Greg Tylka, ISU Extension Plant Pathologist

 

Making Fungicide Application Decisions

Mark Carlton, ISU Extension Field Agronomist

 

More details are posted at http://www.extension.iastate.edu/Pages/eccrops/meetserc.html.

 

 

STRIP-TILL FIELD DAY

Doug Nolte and the Iowa Learning Farm (Iowa State University), hosts

1021 Highway 6, West Liberty, IA

JUNE 22, 2011, 10:30 a.m. – Noon, followed by lunch

The farm is just in Muscatine County near the Johnson County line. Program details will be forthcoming.

 


NORTHEAST IOWA RESEARCH and DEMONSTRATION FARM, Nashua

SPRING FIELD DAY

JUNE 29, 2011, 1 – 4:30 p.m.

Crop progress and the weather

Ken Pecinovsky, Farm Superintendent

 

Climate and crop yield predictions

Elwynn Taylor, ISU Extension Climatologist

 

Corn and soybean disease issues

                        Alison Robertson, ISU Extension Plant Pathologist

 

Field drainage

Matt Helmers, ISU Extension Ag Engineer

 

Nematodes in corn and soybeans

Greg Tylka, ISU Extension Nematologist

The Field Day is free and open to the public.  Pre-registration is not required.  CCA credits ( 1 SW, 1.5 PM, 1 CM) will be available for $20.  For questions, contact Brian Lang at 563-382-2949.

More details are posted at http://www.extension.iastate.edu/Pages/eccrops/meetnerf.html.

 

MUSCATINE ISLAND (horticulture) RESEARCH and DEMONSTRATION FARM, Fruitland

SUMMER FIELD DAY

JULY 19, 2011

Details will be posted soon at http://www.extension.iastate.edu/Pages/eccrops/meetmusc.html.

 

If you have any questions, please feel free to contact the Iowa State University Extension Office.

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Last Update: May 20, 2011
Contact: Jim Fawcett fawcett@iastate.edu


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