CORN
Crop Observation and Recommendation Network

October 15 to October 21, 2001
C.O.R.N. 2001-35

In This Issue:

A) Wheat Planting: Are You Done Yet?
B) Corn Stalk Quality Update
C) Northern Corn Leaf Blight: A Potential Threat
D) Some Reminders on Managing Winter Annual Weeds and Dandelion with Fall Herbicide Applications
E) Agronomic Crop Production Workshops Scheduled

Note to subscribers: This is the last weekly C.O.R.N. newsletter of the season. Next week we will be starting our bi-weekly/monthly newsletter schedule through winter. Your next C.O.R.N. will arrive the week of October 29th.

A) Wheat Planting: Are You Done Yet? - Pat Lipps CORN Questions

The delay in soybean harvest has delayed wheat planting in many regions of the state. The optimum time to plant wheat in Ohio is anywhere from the Hessian Fly Free Date to about 10 to 14 days after this date for your county. As wheat planting is delayed beyond this optimum timing, the chances of reduced yield become more apparent. The effect of planting date on yield is dependent on the weather conditions that occur between the time when the plants emerge and they go into winter dormancy. In general, the best yield comes from plants that develop 3 to 4 tillers in the fall before they go into dormancy. These are the main tillers that produce most of the yield in the spring. Plants that develop from later planting develop fewer main tillers and these plants are more vulnerable to winter injury and frost heaving. Late planted wheat almost always has fewer heads per square foot in the spring than wheat planted at the appropriate time. Of course the length of the growing period in the fall is dependent on when soil temperatures begin to drop such that the plants no longer grow. Most years this occurs in late November or at least by the second week of December. Also the later the planting, the cooler the soil temperatures, and the slower the plants grow. For most northern Ohio areas, wheat planted after about October 20 has a limited chance of achieving high yield.

Manage later planted wheat carefully and understand your risks. Apply about 20 lb nitrogen at planting and increase your normal seeding rate to 1.6 to 2.0 million seed per acre. Since it is likely that each plant will not produce as many tillers, you need to plant more seed to have more plants to make up the difference. If soil conditions are good, plant not less than an inch deep. Shallower planting will only increase the chance of frost heaving. In the spring, check the field at green up to evaluate the winter survival, then apply the amount of topdress nitrogen to achieve a yield goal reasonable for the plant stand.

B) Corn Stalk Quality Update - Pat Lipps CORN Questions

Earlier issues of C.O.R.N. have alerted you to the problems with corn stalk quality in Ohio. Many corn growers are now attempting to harvest corn as quickly a possible but are also facing the need to harvest beans, or possibly plant wheat. There seems to be some areas of the state with more stalk quality problems than other areas, so not all growers are having the same types of problems. Anthracnose stalk rot, Gibberella stalk rot, Fusarium stalk rot and Diplodia stalk rot have been reported in various regions of the state and to various degrees of severity. Up until now most fields have remained standing which has facilitated harvest. Further deterioration of the stalks can occur very quickly when adequate to surplus moisture favors rapid colonization of stalk tissues by fungi. Recent rains over the week end and those predicted for this week will have a negative impact on stalk quality. Stalk moisture is very critical to growth of fungi in stalk tissues. Warm, wet weather is most favorable to fungal growth and most detrimental to stalk quality. Watch the weather forecasts for extended periods of wet weather that could greatly impact the amount of lodging in fields. It would be a good idea to scout fields again for stalk rot and lodging to prioritize fields for harvest. Some hybrids will loose stalk quality more quickly than others so doing another quick check around the farm may help you reschedule field harvest and prevent yield losses due to lodged corn.

C) Northern Corn Leaf Blight: A Potential Threat - Pat Lipps CORN Questions

Northern corn leaf blight was more common in Ohio this past growing season than in the previous 20 years. Basic information on this disease can be found on the Ohio Field Crop Disease web site (http://www.oardc.ohio-state.edu/ohiofieldcropdisease/corn/nclb.htm). This disease produces large tan to brown cigar shaped lesions on the corn leaf. Lesions by be from 2 to 8 inches long and 0.5 to 1.5 inches wide. Leaves with 6 to 8 of these lesions will be nearly dead. Yield losses to northern corn leaf blight have not been recorded in Ohio for many years, but historical information indicates that if the disease occurs early enough in the season, at the beginning of grain fill, yield losses can be quite high. The northern leaf blight fungus survives the winter on old corn residues and is spread in the late spring by wind. Spores can be carried by wind over long distances, but severe epidemics usually occur in fields where the fungus is present on the previous crop residue (continuous corn fields). The only reason northern corn leaf blight is in Ohio fields is because susceptible hybrids are being planted. Over the years this disease has been effectively controlled by planting resistant hybrids. There are two very effective types of resistance (race specific resistance and partial resistance) available in hybrids. Growers are encouraged to choose resistant hybrids to plant in Ohio because of the potential for yield loss from this significant disease. If northern corn leaf blight was present in your fields this past season, you may want to till the corn residues to reduce the over winter survival of the fungus and plant soybeans in those fields next spring. Visit with your seed corn dealer to choose high yielding and disease resistant hybrids to plant in your other fields next year.

D) Some Reminders on Managing Winter Annual Weeds and Dandelion with Fall Herbicide Applications - Loux, Stachler, and Dobbels CORN Questions

This is a condensed version of the detailed article on winter annual weeds that appeared in C.O.R.N. the week of September 17. That article can be found in the C.O.R.N. archive at http://www.ag.ohio-state.edu/~corn/agcrops.html. Anytime during the next four weeks is an ideal time to apply herbicides for control of winter annual weeds and dandelion. Applications during warm weather will result in the most rapid weed death. However, we applied herbicides in mid to late November in our 2000/2001 research, and although activity of some herbicides was slow under the cold conditions, they did control the weeds completely by March. Where the goal is to maximize the residual activity of herbicides such as Canopy XL and Backdraft into next year's soybean crop, we suggest delaying application until at least mid-November when the soil temperatures are lower and the rate of degradation of herbicide is greatly reduced.

Overview of OSU research on winter annuals

OSU weed scientists conducted field research in the fall and spring of 1999/2000 and 2000/2001 to determine the effectiveness of various herbicide treatments for control of common chickweed and purple deadnettle. We had field studies at three locations each year east of Chillicothe, Amanda, and South Charleston. Our research was much more extensive in 2000/2001, with regard to the number of herbicides and rates included. Fall herbicide treatments were applied in mid- to late-November both years, and spring treatments were applied in late March. Results of these studies are summarized below and tables showing all of the data are available at the OSU Weed Science website http://www.oardc.ohio-state.edu/weedworkshop/. We included 2,4-D ester (1 pint/A) with most treatments. Treatments containing glyphosate were applied with ammonium sulfate. All other treatments were applied with crop oil concentrate. Overall, fall treatments provided much more consistent control of chickweed and deadnettle than spring treatments. Among soybean herbicides, few treatments provided more than 80% control of both weeds in March, but a number provided better than 90% control when applied in November. Most of the chickweed and deadnettle (95% or greater) emerged prior to November treatments, but we did observe a few deadnettle emerging in the spring where treatments without residual activity were applied.

Fall herbicide treatments for soybeans providing an average of at least 90% control of chickweed and deadnettle in OSU research:
- Canopy XL (2.5 to 4.5 oz/A) + Express (0.2 oz/A) + 2,4-D ester (1 pt/A)
- Classic (1 oz/A) + Express (0.2 oz/A) + 2,4-D ester (1 pt/A)
- Canopy SP (6.5 oz/A) + 2,4-D ester (1 pt/A)
- Glyphosate (0.75 lb ae/A = 26 oz of Roundup Ultra Max or 32 oz of Touchdown, Glyphomax, others)
- 2,4-D ester (1 pt/A) + Glyphosate (0.38 lb ae/A = 13 oz of Roundup Ultra Max or 16 oz of Touchdown, Glyphomax, others)
- Canopy SP (2.6 oz/A) + Sencor (4 oz/A) + 2,4-D ester (1 pt/A)
- Backdraft (4 pts/A) + 2,4-D ester (1 pt/A)
- Extreme (3 pts/A) + 2,4-D ester (1 pt/A)
- Sencor (4 oz/A) + glyphosate (0.56 lb ae/A - 20 oz of Roundup Ultra Max or 24 oz of Touchdown, Glyphomax, others)
- Sencor (4 oz/A) + Gramoxone (1 qt/A) + 2,4-D ester (1 pt/A)

Fall herbicide treatments for soybeans providing an average of 80 to 90% control of chickweed and deadnettle in OSU research:
- Sencor (8 oz/A) + 2,4-D ester (1 pint/A)
- Backdraft (3 pts/A) + 2,4-D ester (1 pint/A)

Fall herbicide treatments for corn providing an average of at least 90% control of chickweed and deadnettle in OSU research (Note: simazine + 2,4-D ester is effective on most winter annuals but is weak on deadnettle):
- Basis (0.5 oz/A) + 2,4-D ester (1 pt/A)
- Express (0.33 oz/A) + simazine (1 lb ai/A) + 2,4-D ester (1 pt/A)
- Simazine (1 lb ai/A) + Sencor (4 oz/A) + 2,4-D ester (1 pt/A)

Some suggestions for use of 2,4-D ester
We included 2,4-D ester in most treatments because it is economical and helps control dandelion, marestail, and mustards. 2,4-D is generally not effective for control of chickweed or deadnettle, but can have some activity on these weeds. Where dandelion is target weed, use a 2,4-D rate of 1 quart/A unless it is combined with Canopy XL or glyphosate, in which case a rate of 1 pint/A may be adequate.

Fall herbicide options for dandelion
Dandelion control in the spring has been variable and extremely slow with many herbicide treatments, especially when the dandelions are well established. Fall is an excellent time to apply herbicides for dandelion control. We suggest applying by early November when control of dandelion is a goal. Herbicide options include:
- 2,4-D ester (1 qt/A)
- Glyphosate (0.75 lb ae/A = 26 oz of Roundup Ultra Max or 32 oz of Touchdown, Glyphomax, others)
- 2,4-D ester (1 pt/A) + glyphosate (0.56 lb ae/A = 20 oz of Roundup Ultra Max or 24 oz of Touchdown, Glyphomax, others)
- Canopy XL (2.5 to 4.5 oz/A) + Express (0.2 oz/A) + 2,4-D ester (1 pt/A)
- 2,4-D ester (1 pt/A) + Backdraft (4 pts/A)

Fall herbicide options for marestail (horseweed)
Marestail can emerge throughout much of the year, but the majority emerges in the fall. Fall herbicide options include:
- 2,4-D ester (1 pt/A)
- Glyphosate (0.56 lb ae/A = 20 oz of Roundup Ultra Max or 24 oz of Touchdown, Glyphomax, others)
- 2,4-D ester (1 pt/A) + Glyphosate (0.38 lb ae/A = 13 oz of Roundup Ultra Max or 16 oz of Touchdown, Glyphomax, others)
- Backdraft (4 pts/A)
- 2,4-D ester (1 pt/A) + Backdraft (3 pts/A)
- 2,4-D ester (1 pt/A) plus Sencor
- 2,4-D ester (1 pt/A) plus Python or Canopy SP or XL (* as long as the fields do not have ALS-resistant marestail)

Suggestions on adjuvants
- All treatments containing glyphosate should include ammonium sulfate, and some glyphosate products also require the addition of nonionic surfactant.
- All treatments not containing glyphosate should generally include crop oil concentrate at the rate of 1% v/v or 1 quart per acre (when applying in a spray volume of less than 15 gallons/A). Some labels specify the use of 28% nitrogen solution or ammonium sulfate also.

E) Regional Agronomy Meetings Scheduled - Ray Wells CORN Questions

Mark your calendars for one of the upcoming Regional Agronomy Meetings to be held this late fall and winter throughout Ohio. The following is a listing of the offerings.

Regional Agronomy Meeting Locations

December 18, 2001
Henry County, Deshler
Bavarian Haus
St. Rt. 18, 2 miles west of Deshler
Host Agent: Alan Sundermeier
OSU Extension, Henry County
104 E. Washington St.,
Hahn Center, Suite 107
Napoleon, OH 43545-1646
419-592-0806
sundermeier.5@osu.edu

December 19, 2001
Marion County, Waldo
All Occasion Catering
Corner of SR 47 & SR 229
(South edge of Waldo)
Host Agent: Steve Ruhl
OSU Extension, Morrow County
871 W. Marion Road, Suite 102
Mt. Gilead, OH 43338-1088
419-947-1070
ruhl.1@osu.edu

December 19, 2001
Champaign County, Urbana
Champaign Co. Community Center, Auditorium
1512 S. U.S. Highway 68
Host Agent: Barry Ward
OSU Extension, Champaign Co.
1512 S. US Highway 68, Suite B100
Urbana, OH 43078
937/484-1526
ward.8@osu.edu

December 20, 2001
Muskingum County, Dresden
Dresden United Methodist Church
1014 Main Street
Host Agent: Mark Mechling
OSU Extension, Muskingum County
225 Underwood Street, Room 6
Zanesville, OH 43701-3789
740-454-0144
mechling.1@osu.edu

January 15, 2002
Wayne County, Wooster
Fisher Auditorium, OARDC
1680 Madison Road (St. Rt. 250)
Host Agent: Mike Miller
OSU Extension, Medina County
120 West Washington Street
Medina, OH 44256-2269
330-725-4911
miller.26@osu.edu

January 15, 2002
Portage County, Kent
Holiday Inn
State Route 43 (North)
Exit on I-76 east of Akron
Host Agent: Kevin O'Reilly
OSU Extension, Portage County
6970 SR 88
Ravenna, OH 44266-9150
330-296-6432
oreilly.18@osu.edu

January 16, 2002
Highland County, Hillsboro
Highland County Training
and Employment Center
1575 North High Street (U.S. 62)
Host Agent: John Grimes
OSU Extension, Highland County
119 Governor Foraker Place
Hillsboro, OH 45133-1092
937-393-1918
grimes.1@osu.edu

January 18, 2002
Preble County, Eaton
Bruner Arena, Preble County Fairgrounds
22 South Franklin Street
Host Agent: Bonnie Norris
OSU Extension, Preble County
119 S Barron St.
Eaton, OH 45320-2394
937-456-8174
norris.84@osu.edu

For more information on these Regional Agronomy Meetings including resource speakers and registration information see the following website:
http://www.ag.ohio-state.edu/~corn/programs.html

Readers can subscribe electronically to this newsletter by sending an e-mail message to: corn-out-on@postoffice.ag.ohio-state.edu. A successful subscription message will receive by an automatic reply from the listserv. Contact your local Ohio State University Extension Office or e-mail labarge.1@osu.edu if you have problems subscribing.

Past versions of C.O.R.N. can be found on the World Wide Web at: http:/www.ag.ohio-state.edu/~corn/archive/

C.O.R.N. is a summary of crop observations, related information, and appropriate recommendations for Ohio Crop Producers and Industry. C.O.R.N. is produced by the Ohio State University Extension Agronomy Team, State Specialists at The Ohio State University and Ohio Agricultural Research and Development Center. C.O.R.N. Questions are directed to State Specialists, Extension Associates, and Agents associated with Ohio State University Extension and the Ohio Agricultural Research and Development Center at The Ohio State University.

Editor: Barry Ward        Web Editor: Tom Rosati

Information presented above and where trade names are used, they are supplied with the understanding that no discrimination is intended and no endorsement by Ohio State University Extension is implied. Although every attempt is made to produce information that is complete, timely, and accurate, the pesticide user bears responsibility of consulting the pesticide label and adhering to those directions.

All educational programs conducted by Ohio State University Extension are available to clientele on a nondiscriminatory basis without regard to race, color, creed, religion, sexual orientation, national origin, gender, age, disability or Vietnam-era veteran status.

Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, Keith L. Smith, Director, Ohio State University Extension.

TDD # 1 (800) 589-8292 (Ohio only) or (614) 292-1868

  | C.O.R.N. | Newsletter | Archive | Search | Questions? | Ohioline | Publications |