http://www.ag.ohio-state.edu/~corn/ |
|
In This Issue:
A) A Good Investment, Wheat Seed Treatments
B) Assessment Of European Corn Borer Injury
C) Drought-Stressed Corn, Grain Harvest Considerations
D) Precision Farming And Drought-Stressed Corn
It is our normal recommendation that all wheat seed be treated with a fungicide to control loose smut, common bunt, Fusarium scab and Stagonospora nodorum. Several wheat growers have asked if seed treatments would be a good investment since these diseases were not a problem in 1999 and the quality of this year’s wheat seed is excellent. In addition, seed testing labs report very high germination percentages for Ohio produced wheat.
High germination percentage from a laboratory test is a good way of evaluating germination in the field under normal soil temperatures and moisture levels. Unless rainfall patterns change drastically over the next two weeks, most farmers will be faced with planting wheat into very dry soils. These conditions can delay germination, requiring seed to remain in soil for an extended period of time. Young seedlings find it difficult to maintain vigorous growth under dry conditions and the stress makes them vulnerable to infection by soil inhabiting fungi like Fusarium. Stressed plants often do not survive the harsh winter conditions we sometimes experience or they grow slowly and produce fewer tillers in the spring. The added protection of a seed treatment fungicide will help seedlings grow this fall to provide the 2 to 3 tillers necessary to survive the winter.
There are several seed treatment fungicides available for wheat. The newer products have given excellent results in Ohio trials using both conventional and no-till management systems. Raxil-Thiram and Dividend XL are two newer seed treatments that have shown consistent yield performance as compared to the older products on the market. These newer products have similar performance for diseases that occur under Ohio production systems and provide excellent protection against the seed borne diseases listed above.
The added protection from a seed treatment will help fall establishment and winter survival. Stand loss from winter injury has been the cause of lower yields in years past. Using an effective seed treatment can help produce a vigorous stand of wheat that will help insure yields next summer.
As corn dries down in the field, it is a good time to evaluate stalk injury due to European corn borer. Such an injury assessment will provide information relevant to the need for corn borer injury prevention and the justification of growing Bt-corn.
This growing season began with a minimal level of overwintering corn borers, which resulted in very low levels of first generation corn borer injury. However, long hot growing seasons tend to increase corn borer activity, which will become evident as second generation infestations. At this point in time, late instar larvae of second generation corn borer can be found in corn stalks. These larvae will overwinter in the corn stubble and broken stalks. However, there is a possibility that these larvae will pupate and emerge to cause a third generation. Dr. Welty, the OSU Vegetable Entomologist, has observed signs of such activity in pepper fields. The third generation often results in a suicide mission for corn borer populations since the young larvae will not likely find suitable hosts in time for survival, which may reduce overwintering populations.
Assessment of corn borer infestations at this time should be based on a random selection of about 20 corn plants, which should be split and inspected for presence of cavities and corn borer larvae. An inspection of three Bt-corn isolines in plots at the Western Branch last week found injury levels ranging from 0.20 to 0.75 cavities per plant and 0.20 to 0.44 larvae per plant for non-Bt hybrids. This level of corn borer injury and infestation is higher than that observed in 1998 (0.15 cavity per plant) and less than that observed in 1997 (0.91 cavity per plant). Inspection of three Bt-corn hybrids detected no corn borer injury. Corn borer infestation levels observed at the Western Branch during the last three years have been consistently lower than 1.0 cavity per plant (minimal economic level of injury warranting consideration of the use of Bt-corn). Additional information on plots at the Northwest Branch Station will be forthcoming and trials at both the Western and Northwestern branch stations will be taken to yield.
This year's widespread drought has resulted in smaller than normal ears, and much greater percentage of "nubbin" ears in many fields. In addition, plants are shorter than normal with reduced ear heights. As a result of these conditions, some combine and harvesting adjustments may be necessary. The following are management suggestions from ag engineers and equipment specialists on harvesting drought-damaged crops.
The following article is by Bill Casady from the University of Missouri Integrated Pest & Crop Management Newsletter (September 3, 1999 issue) and contains information that could be useful to many corn growers in Ohio.
Drought stricken areas have already begun to show up in reductions to both yield and quality. If you are already harvesting corn sooner than expected you are not alone. Although average moisture contents may be much lower than normal for this time of year, drydown rates within fields will vary considerably by soil type and/or local moisture availability within fields.
There are two logical approaches to "fitting in" with the variability that will characterize the 1999 harvest:
The first approach is a logical approach to time management and overall quality. An early harvest has advantages, especially if weather deteriorates toward the wet side later in the season. Just keep an eye on concave/rotor clearances and fan speed and make adjustments throughout the field depending on the "site-specific" condition of the crop. Overall threshing and separating performance will be poorer than usual, but a site-specific approach will pay off in reducing harvest losses and minimizing both damage to grain and accumulation of foreign matter.
The site-specific approach will not be an exact science and can even be a mess to keep track of. But livestock farmers can capitalize on diversity by feeding drought-stressed grain to livestock and marketing higher quality grain. Corn stressed by drought will generally have lower test weights and will be docked when marketed, but it is still a good feed source and will often have a higher protein content than average corn.
Reduced quality is practically assured and should be the focus of harvest management for drought-stricken areas. Poorly developed ears are more difficult to thresh and separate; kernel size will vary considerably even on a single ear; and cobs are more likely to break up and increase foreign matter in samples. Since healthy weeds seem to grow under a variety of weather, weeds may also become a factor, leaving higher amounts of green plant tissue in the sample.
Increased efforts to maximize sample quality and cleanliness will pay off both in drying and storage as well as marketing. Foreign matter restricts airflow during drying and also later on during aeration. Reduce problems in the center of the bin by screening out fines and spreading grain evenly. Just like electricity, airflow seeks the path of least resistance. A cone in the center of a bin will have a higher concentration of fines as well as greater resistance to airflow from the increase in depth (one of the many reasons grain at the top and center of a bin is the first to go out of condition).
As always, remember to dry grain quickly and the best approach is to dry shallow layers of grain with lots of air; use heat with care. Grain at the top does not dry until the grain below it is dry. As grain at the top awaits the "drying front" it begins to spoil (another reason grain at the top of the bin is the first to go out of condition). Finally, if you do not have an immediate use for poorer quality grain, "keep the best and sell the rest". Store only high quality grain.
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
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.
Contributors to C.O.R.N. this week include: State Specialists: Hal Willson (Entomology), Peter Thomison (Horticulture and Crop Sciences), Pat Lipps (Plant Pathology), and Anne Dorrance (Plant Pathology); District Specialist: Ed Lentz (Agronomy); Extension Associate: Jeff Stachler (Horticulture and Crop Science); Extension Agents: Steve Prochaska (Crawford), Dennis Baker (Darke), Larry Lotz (Fayette), Clark Hutson (Seneca), and Andy Kleinschmidt (Van Wert)
Editor: Ed Lentz Web Editor: Steve Lichtensteiger
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
| Drought'99 | C.O.R.N. | Newsletter | Archive | Search | Questions? | Ohioline | Publications |