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Mid November, 2000
C.O.R.N. 2000-37
In This Issue:
A) Impact of Corn Border on Ohio Corn Yields In 2000
B) A Few Reminders on Winter Annuals
C) Regional Agronomy Meeting Series Set For 2000-2001
D) C.O.R.N. Schedule Change For Winter
Since 1997, we have been evaluating Bt-corn hybrids and comparable non-Bt isolines at the OARDC Western and Northwestern Branch Stations. From 1997 to 1999, average yields of the Bt-corn hybrids evaluated were equivalent to the comparable non-Bt isolines. Occasionally a given Bt-hybrid would generate a significantly higher yield than the equivalent non-Bt isoline, but the difference between average yields of Bt-corn hybrids and comparable isolines evaluated at the two research stations was less than a bushel after three years of replicated trials. By the end of the 1999 harvest season, we were having serious doubts about the benefits of Bt-corn in Ohio, where the corn borer tends to have a marginal economic impact on corn yields.
In the 2000 growing season, we continued our comparison Bt-corn hybrids (specifically, four Yieldgard hybrids) and equivalent non-Bt isolines at the Western and Northwestern branch stations. In addition, non-replicated field trials of the same hybrids were conducted at eight county on-farm sites with the cooperation of OSU Extension agents, growers and agribusiness field personnel. Participants included Highland, Fayette, Licking, Knox, Darke, Crawford, Allen and Van Wert OSU Extension county programs.
At the Western branch station, the past history of low levels of corn borer injury resulting in minimal differences between Bt-corn and non-Bt isolines continued. Corn borer injury on non-Bt isolines averaged 0.5 cavities per plant and the average yield of four Bt-corn hybrids was 0.5 bu/acre less than the comparable non-Bt isolines. In summary, the Western Branch in Clark county represents one area in the state where corn borer impact on yields is marginal and one may question the need for growing Bt-corn.
In contrast, the field trial comparing the same Bt-corn and non-Bt hybrids at the Northwestern Branch OARDC in Wood County was hit hard this year by corn borer. In early September, non-Bt corn hybrids at the NW Branch averaged 4.75 cavities per plant and subsequent yields of Bt-corn hybrids averaged 11.4 Bu/acre higher than the equivalent non-Bt isolines. The heavy infestation of the 2000 growing season raised the four year average difference between Bt-corn and non-Bt isolines to 4.3 Bu/acre, which over time would justify the premium fee linked to the use of Bt-corn hybrids. In summary, the results from the NW Branch demonstrate that areas subject occasional severe infestations of corn borer may benefit from the use of Bt-corn, despite the fact that yield differences between Bt-corn and non-Bt corn hybrids may be minimal for two or three years. The last heavy corn borer activity at the NW Branch was in 1996, when corn borer injury in our trials averaged 3.9 cavities per stalk. In that year, we were not comparing Bt-corn hybrids to equivalent isolines and a fair comparison of yields was not possible.
In the on-farm trials of Bt-corn and non-Bt corn hybrids this year, corn borer injury ranged from 0.15 to 1.85 cavities per plant in non-replicated trials located in eight counties. To date, the difference in yields between Bt-corn and non-Bt corn hybrids reported from six on-farm trial sites average 8.0 Bu/acre. Yields of Bt-corn were higher than that of non-Bt corn at every trial site, including the sites having relatively low levels of corn borer infestation this year. Although the yield results observed in the on-farm trials are very significant this year, one should raise a question in regard to what the long-term yield gain may be over time.
Corn borer infestations this year clearly had an impact on yield. Examination of field plots in September found a combination of 1st brood stalk injury, 2nd brood stalk injury, an unusual level of shank injury plus cob injury. A high proportion of 2nd brood larvae were found in the ear zone and the presence of possible 3rd brood infestations were noted. At the NW Branch station, where corn borer infestation was very heavy, almost every shank was tunneled by a corn borer larvae which would have a significant effect on ear formation and ear drop if harvest was delayed. In addition, significant stalk rot injury was observed while splitting stalks in September. Presumably, stalk rot injury was enhanced by corn borer injury. But, differences in stalk rot injury between hybrid lines were more obvious than differences between Bt-corn hybrids and their equivalent non-Bt isolines.
In summary, the long-term benefits of growing Bt-corn are dependent on the history of corn borer activity in an area over time. In a situation such as that observed at the Western Branch Station, where corn borer activity is marginal, planting of Bt-corn may result in a negative economic benefit. In contrast, the situation at the Northwestern Branch Station demonstrates that Bt-corn may generate a positive benefit over time if losses from occasional heavy corn borer outbreaks are prevented. In other areas of the state, annual observations of corn borer injury and yields over time are needed to evaluate the long-term benefits of Bt-corn.
The schedules and locations for the Regional Agronomy Meeting series to be held across the state in January and December are set. The series is designed to provide high quality, timely one-day update sessions for farmers and agriculture industry professionals in agronomic crop production topics. Topics are short 30-40 minute presentations to provide solutions to current or anticipated problems and highlight current research of interest.
Commercial and private pesticide applicator credits will be given along with Certified Crop Advisor Credits. Topics vary to by site meet local needs. The cost of the program is $15 if registrations are in 1 week prior to the meeting and $20 at the door (space permitting).
The programs are a joint effort of Agri-industry, Ohio Corn Growers, Ohio Soybean Council, Ohio State University Extension and the OSU's Agronomic Crops Team. Sites, agendas and registration can be found at http://www.ag.ohio-state.edu/~corn/program.html. Below are the dates, county locations, and host agent contact information for these meetings. Call the numbers listed below or contact any office of Ohio State University Extension for complete program details.
The release timing for this newsletter has gone to it's winter schedule. We will continue to publish the newsletter twice per month with a first of the month and mid month release until April where we will return to the weekly schedule. We will provide you an update on a variety of issues from winter meetings and current research being conducted at the Ohio State University and other Land Grant Universities. If you have particular questions or topics you would like to see addressed in the newsletter send an e-mail to corn-questions@postoffice.ag.ohio-state.edu.
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.
State Specialists: Pat Lipps & Anne Dorrance (Plant Pathology), Hal Willson (Entomology), Mark Loux (Weed Science). Extension Agents: Roger Bender (Shelby), Dave Jones (Allen), Barry Ward (Marion), Glen Arnold (Putnam), Greg La Barge (Fulton), Howard Siegrist (Licking) and Steve Prochaska (Crawford).Editor: Greg LaBarge 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
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