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Early February, 2001
C.O.R.N. 2001-2
In This Issue:
A) A Friend Lost
B) Ohio Has ALS-Resistant Shattercane
C) 2000 Evaluations of Nutritionally Enhanced Corn
D) Update on OSU Winter Annual Research
E) New Herbicide Update
F) Poor Seed Production Weather to West May Lead to Short Supplies
in Ohio
G) Answers to the Soybean Cyst Nematode Worksheet
We are saddened to report the loss of a colleague and friend, Dr. Harold Willson, Extension Specialist, Integrated Pest Management, The Ohio State Univesity. Dr. Willson died January 23, 2001 at St. Lukes Hospital, Maumee. Hal was an important contributor to this newsletter and his loss will be felt throughout Ohio. We have a tribute to Dr. Willson planned for our next newsletter.
There are several specialty corns currently being marketed for value enhanced (or "value-added") grain production. These include the TopCross, Supercede, and NutriDense corns. These specialty corns were developed with improved nutritional traits to enhance the feed value of grain. Nutritionally enhanced grains produced by these specialty corns offer major advantages over No. 2 yellow corn because they contain more protein, essential amino acids, and energy (oil) which can help livestock feeders reduce reliance on costly ingredients and supplements.
Unlike the TopCross high oil corn production system that involves the use of blends, the Supercede and NutriDense nutritionally enhanced corns are single cross hybrids. Dow AgroSciences and ExSeed Genetics have licensed the Supercede and NutriDense corn hybrids to seed companies for distribution, respectively.
Evaluations of nutritionally enhanced corns in 2000 were conducted at the OSU-OARDC Research Farm at Wooster in northeast Ohio and the OSU-OARDC Northwest Branch Research Farm near Hoytville in northwest Ohio. Fifteen nutritionally enhanced corns including two Supercede hybrids, 13 NutriDense hybrids, and a single cross high oil corn hybrid) from nine seed companies were planted at each site (Supercede and NutriDense are trademarks of Dow AgroSciences and ExSeed Genetics, respectively.) Four conventional (low oil) single cross hybrids were also included as checks.
In 2000, grain yields of the nutritionally enhanced hybrids ranged from 84 to 132 Bu/A at Hoytville and from 66 to 117 Bu/A at Wooster. The nutritionally enhanced hybrids averaged yields that were 14% and 30% less than the conventional hybrids at Hoytville and Wooster, respectively. This is in marked contrast to the 1999 tests in which yields of most of the Supercede and NutriDense hybrids were not significantly different from the conventional check. In 2000, severe stalk lodging was a major factor contributing to the lower yields of the nutritionally enhanced hybrids at Wooster. Common rust was more serious problem in the nutritionally enhanced corns than conventional corns at Hoytville. Nevertheless, at both locations in 2000, there were Supercede and NutriDense hybrids that produced yields that were not significantly different from the conventional checks.
In 1999 and 2000, grain produced by the NutriDense, Supercede, and single cross high oil corn was characterized by higher oil content than grain of normal corn hybrid (in 2000, 5.1% vs. 4.0 % at Hoytville, 5.5% vs. 4.3% at Wooster; in 1999, 5.9% vs. 4.2% at Hoytville, 6.0% vs. 4.2% at Wooster). In 2000, there were significant differences in grain oil content among the nutritionally enhanced hybrids at each location, with oil levels ranging from 4.7% to 6.0% at Hoytville and from 5.0% to 6.5% at Wooster. Comparable variation in oil content among the nutritionally enhanced corns was also observed in 1999.
At Hoytville and Wooster in 2000, most of the nutritionally enhanced hybrids exhibited significantly higher grain protein levels than the normal corn. Grain protein levels of nutritionally enhanced hybrids averaged 1.9 percentage points higher than the conventional corn at Hoytville, but only 0.9% higher at Wooster. Similar differences in grain protein content were observed between test locations in 1999. At both locations, there were also significant differences in grain protein among the nutritionally enhanced corn hybrids. Averaged across locations, starch levels in grain were 2.8 percentage points less in nutritionally enhanced corn compared to normal corn.
Full results of the 2000 Nutritionally Enhanced Corn will shortly be available on the web at the following address: http://www.ag.ohio-state.edu/~hocorn/NECrep00.htm
TopCross is a registered trademark of DuPont Specialty Grains, Supercede and NutriDense are trademarks of Dow AgroSciences and ExSeed Genetics, respectively.
OSU weed scientists are currently conducting a total of 11 field studies at four sites on the control of winter annual weeds prior to corn or soybeans. We applied herbicide treatments in mid-November through early-December, and will apply additional treatments in March and just prior to planting. The fall treatments were applied under fairly cold conditions, especially those in early December, but all were applied prior to the December snows. These studies were rated over the past several weeks to get an idea of herbicide effectiveness on chickweed and deadnettle. There seems to be better herbicide activity in general at the sites treated in mid-November. Overall, the control at this time seems to be less effective than last year, probably due to much colder conditions around the time of application. However, some treatments are still providing excellent control.
Herbicides with contact activity appear to be more effective than systemic herbicides, with a few exceptions, but it is possible that control could still increase in some treatments. The most effective treatments for control of chickweed at this point include: Sencor + Gramoxone (4 oz + 2 pts); Sencor (8 oz); Sencor + Python (4 + 0.8 oz); Command Xtra (75% of use rate); Express (0.2 oz) + Canopy or Canopy XL; and Canopy DF + Sencor (2 + 4 oz). The most effective treatments for control of deadnettle at this point include: Sencor (8 oz); Sencor + Python (4 + 0.8 oz); and Command Xtra (75% of use rate). The Canopy XL + Express treatment was about 20% less effective on deadnettle than the previous three treatments, and was also somewhat more variable on chickweed than some of the other treatments listed (again, this may be due to a reduction in systemic herbicide activity under cold conditions). Glyphosate treatments have shown little activity in this winter's studies so far. We will be rating these studies throughout the next several months to see if the weeds will still die after showing few symptoms for two months or more. Most of these treatments were applied with crop oil concentrate (1 qt/A) and 2,4-D ester (1 pint/A), but glyphosate treatments were applied with ammonium sulfate only. While 2,4-D has little activity on chickweed and marginal activity on deadnettle when applied alone, it does help control marestail, dandelion, and mustard species.
Keep in mind that winter annuals can continue to increase in size throughout the winter and early spring, depending upon weather. As a result, higher rates of herbicide may be needed in later winter or early spring, compared to late-fall applications. To maximize herbicide effectiveness, try to apply during periods of relatively warm weather if possible. Fields that are treated in late winter or early spring should be scouted again near the time of planting to see if additional burndown herbicide is needed at that time.
Define (Aventis) is a 60% WDG formulation of flufenacet, the acetamide component of Axiom, for preplant/preemergence use in corn. Define does not contain metribuzin, and grass/broadleaf control is similar to Dual II Magnum, Frontier, and alachlor products. Flufenacet has been less effective in yellow nutsedge than Dual II Magnum. This product will be sold primarily in programs with other Aventis products such as Liberty and Balance.
Steadfast (DuPont) is a postemergence premix of nicosulfuron (Accent) plus rimsulfuron (grass control component of Basis) in a 2:1 ratio. This product may be slightly less effective on annual grasses than Accent, which should be reflected by the maximum grass size specified on the label.
Outlook (BASF) contains dimethenamid-P, the more active form of dimethenamid (Frontier). This change is similar to the change from Dual II to Dual II Magnum, where s-metolachlor replaced metolachlor. Weed control and crop safety properties are unchanged between Outlook and Frontier, but the amount of active ingredient per acre is reduced due to the higher specific activity of the former.
Boundary (Syngenta) is a premix of s-metolachlor (Dual II Magnum) plus metribuzin (Sencor) for soil-applied grass and broadleaf control in soybeans. This product replaces Turbo, but has less metribuzin and more metolachlor activity than Turbo, on a per acre basis.
Command Xtra (FMC) is a co-pack of clomazone (Command) plus sulfentrazone (Authority) for soil-applied grass and broadleaf control in soybeans. This product controls velvetleaf, lambsquarters, black nightshade, pigweeds, and waterhemp, but is weak on ragweeds and cocklebur.
Gauntlet (FMC) is a co-pack of cloransulam (FirstRate) plus sulfentrazone (Authority) for soil-applied broadleaf control in soybeans. This mix will control most broadleaf weeds, and can suppress grasses for several weeks after planting. Sulfentrazone has almost no activity on ragweeds, so Gauntlet (like FirstRate and other ALS inhibitors) will not control ALS-resistant common and giant ragweed.
Valor (Valent) should be labeled for preplant/preemergence use in soybeans sometime in 2001. The active ingredient, flumioxazin, is a PPO inhibitor - the same mode of action as Authority. Valor controls small-seeded broadleaf weeds, including pigweeds, lambsquarters, black nightshade, and waterhemp, and suppresses a few others.
Callisto (Syngenta) will be labeled sometime in the near future for use in corn. The active ingredient, mesotrione, is similar to Balance in mode of action. Callisto has less activity on grasses than Balance but better crop safety. While mesotrione has both soil-applied and postemergence activity, it appears that Callisto may first be promoted for postemergence use in combination with low rates of atrazine.
For more information about herbicide selection see Bulletin 789 Weed Control Guide for Ohio Field Crops-2001 edition available at your local Extension Office. The Herbicide Selector computer program has been updated and is available for download on-line at: http://ohioline.ag.ohio-state.edu/lines/acrop.html#SFTWARE.
Many seed producing areas to the west of Ohio experienced poor production weather in 2000 like Ohio had in 1999. The result is that seed quality in those areas is very poor as was the case in Ohio. Western seed companies are currently purchasing large quantities of seed from Ohio's seed producers. Ohio soybean farmers should book their seed needs as soon as possible to make sure they will have seed to plant. The expected switch of 10% to 15% of the corn acreage to soybeans throughout the Midwest will further increase the demand for soybean seed needed for 2001 planting.
The graphs at http://www.ag.ohio-state.edu/~corn/library/articles/scnworks.html are the "answers" to the worksheet handed out at the Regional Agronomy Schools. We hope you did your homework! The numbers came from fields in Ohio, where we have multiple year data but most came from Dr. Mac Riedels crop rotation study. THESE ARE GENERAL TRENDS. For the lawyers and bean counters out there, this is the trend that we have seen over and over again, there are many environmental factors, weeds, soil sampling techniques that all influence what the actual SCN numbers are in any given field.
We developed this worksheet for Regional Agronomy Meetings and soybean short courses to demonstrate how cyst populations can be managed with crop rotation. Crop rotation is a VERY effective tool in managing soybean cyst nematodes. This is how it works. Every time you plant a non-host crop in a field, you are starving the nematodes that hatch and look for something to feed. If there is nothing to feed on, they die, thereby reducing the populations.
Soybean Cyst Nematode populations increase 10-fold in newly infested fields with every susceptible soybean crop. As their numbers increase (over 5,000+) they begin to compete with each other for feeding sites and food and populations only increase 3 to 6 fold. This is very dependent on soil type and the environmental conditions that exist in a given field during the production season. Populations of cyst only decline by ½ for every year of a non-host crop - PROVIDED that all alternate hosts (weeds) are controlled.
The resistance to soybean cyst nematode is measured as a proportion. The number of nematodes that can successfully reproduce on a resistant bean compared to a susceptible bean. Which means that SOME nematodes will reproduce on a resistant soybean. We have found in Ohio, when resistant beans are planted the first few times - three things may happen: 1) The population will decline, 2) Stay the same OR 3) Will increase. However, we have always seen when resistant beans are planted continuously, the populations always increase and at the 10-fold level.
We hope that this exercise will help everyone to understand how crop rotation works as a soybean cyst nematode and general disease management tool.
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), Peter Thomison (Corn Production), Jim Beuerlein (Soybeans & Small Grain), Mark Loux (Weed Science), Jeff Stachler (Weed Science) District Specialists: Ed Lentz (Agronomy) Extension Agents: Mike Estadt (Pickaway), Andy Kleinschmidt(Van Wert), Roger Bender (Shelby), Dave Jones (Allen), John Barker (Knox), Steve Bartels (Butler), Ray Wells (Ross), Clark Hutson (Seneca), Barry Ward (Champaign), Dennis Baker (Darke), John Hixson (Union), Bruce Clevenger (Defiance), Gary Wilson (Hancock), Greg La Barge (Fulton), Howard Siegrist (Licking), Glen Arnold (Putnam) 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.
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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.
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