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In This Issue:
A) Evaluation of Bt-Corn and Non-Bt Isolines in Ohio
During the past three years, trials including multiple hybrids of Bt-corn and comparable isolines have been conducted at the Western and Northwestern Branch Stations. The goal of this trial is to evaluate yield benefits that may be attributed to the use of corn that has been genetically modified to prevent losses due to annual infestations of European corn borer (ECB). Results of trials conducted during the 1999 growing season are presented in Table 1.
Table 1 - Comparison of Bt-Corn Hybrids and Non-Bt Isolines at the Western and Northwestern Branch Stations, 1999.
| Treatment | Properties | Stand per 100 Row Ft | ECB Obs. / Cavities | Plant Larvae | Yield Bu./ Ac. |
| Western Branch Station, Clark County | |||||
| Asgrow 730 | Non-Bt | 98.50 b | 0.20 | 0.20 | 145.9 |
| Asgrow 730Bt | Yieldgard | 93.75 b | 0.00 | 0.00 | 137.6 |
| DeKalb 647 | Non-Bt | 105.75 ab | 0.70 | 0.55 | 156.2 |
| DeKalb 647Bt | Yieldgard | 98.25 b | 0.00 | 0.00 | 137.6 |
| Garst 8481 | Non-Bt | 93.75 b | 0.75 | 0.55 | 133.4 |
| Garst 8481Bt | Starlink | 116.75 a | 0.00 | 0.00 | 144.8 |
| Northwestern Branch Station, Wood County | |||||
| Asgrow RX601 | Non-Bt | 130.9 a | 1.10 | 0.75 | 166.0 |
| Asgrow RX601YG | Yieldgard | 131.3 a | 0.00 | 0.00 | 163.7 |
| DeKalb 595 | Non-Bt | 128.4 ab | 0.90 | 0.60 | 171.7 |
| DeKalb 595Bt | Yieldgard | 124.1 b | 0.00 | 0.06 | 161.3 |
| Garst 8481 | Non-Bt | 128.8 a | 1.25 | 0.95 | 168.7 |
| Garst 8481Bt | Starlink | 128.3 ab | 0.00 | 0.00 | 163.6 |
Means in a column followed by the same letter are not significantly different @ P = 0.05.
-Bt-corn hybrid suppressed ECB injury to minimal levels. However, ECB infestations observed in non-Bt corn isolines at both the Western and Northwestern Branch Station trials were marginal in regard to causing economic losses.
-At the Western Branch, stand loss due to cutworm infestation was prevented by the Garst 8481 Bt hybrid, which includes the Starlink trait. This is the first case of significant prevention of a natural infestation of black cutworm injury documented in a Ohio replicated field trial (and possibly within the mid-west region).
-Differences in yield observed between Bt-corn hybrids and non-Bt corn isolines evaluated were not significant.
A summary of results observed in three years of field evaluations of Bt-corn hybrids and equivalent non-Bt isolines conducted at both the Western and Northwestern Branch stations is presented in Table 2.
Table 2 - Evaluation of Stand, Corn Borer Infestation and Yield of Bt-Corn Hybrids and Non-Bt Isolines at two OARDC Research Stations from 1997 to 1999.
| Year of Trial | No. Hybrids Evaluated | Stand per 100 Row Ft. | ECB Obs. Per Cavities | Plant Larvae | Yield Bu/A |
| Western Branch Station, Clark County | |||||
| 1997 | 4 Bt-Corn | 137.7 | 0.15 | 0.01 | 156.5 |
| 4 Isolines | 135.6 | 0.91 | 0.26 | 152.2 | |
| 1998 | 3 Bt-Corn | 136.1 | 0.02 | 0.00 | 131.5 |
| 3 Isolines | 130.0 | 0.15 | 0.11 | 130.2 | |
| 1999 | 3 Bt-Corn | 102.9 | 0.00 | 0.00 | 140.0 |
| 3 Isolines | 99.3 | 0.55 | 0.43 | 145.2 | |
| 3 Yr. Avg. | Bt-Corn | 125.6 | 0.06 | 0.00 | 142.7 |
| Isolines | 121.6 | 0.54 | 0.27 | 144.5 | |
| Northwestern Branch Station, Wood County | |||||
| 1997 | 4 Bt-Corn | 116.4 | 0.20 | 0.08 | 176.1 |
| 4 Isolines | 114.7 | 1.66 | 0.45 | 175.5 | |
| 1998 | 3 Bt-Corn | 123.5 | 0.00 | 0.00 | 174.9 |
| 3 Isolines | 114.5 | 0.07 | 0.12 | 163.8 | |
| 1999 | 3 Bt-Corn | 127.9 | 0.00 | 0.02 | 162.9 |
| 3 Isolines | 129.4 | 1.08 | 0.77 | 168.8 | |
| 3 Yr. Avg. | Bt-Corn | 122.6 | 0.07 | 0.03 | 171.3 |
| Isolines | 119.5 | 0.94 | 0.45 | 169.4 | |
· The bottom line of the results presented in the preceding table is that the corn yields of Bt-Corn hybrids and their non-Bt isolines evaluated at two locations in Ohio over a three year time period are equal.
· Exceptions may exist, but the results demonstrate that corn borer impact over time on Ohio corn is not significant and that the benefit derived from an investment in Bt-Corn may not be warranted under Ohio growing conditions.
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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.
Contributors to C.O.R.N. include: State Specialists: Anne Dorrance and Pat Lipps (Plant Pathology), Hal Willson (Entomology) and Peter Thomison (Corn Production); District Specialist: Ed Lentz (Agronomy); Extension Agents: Barry Ward (Champaign), Steve Prochaska (Crawford), Larry Lotz (Fayette), Greg La Barge (Fulton), and Roger Bender (Shelby).
Editor: Greg LaBarge Web Editor: Nathan Watermeier
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