CORN
Crop Observation and Recommendation Network

April 16-20, 2001
C.O.R.N. 2001-9

In This Issue:

A) Reminders On Wheat Herbicides
B) Winter Wheat Growth Rapid, Tiller Development Good, Cold Weather Should Cause Little Problems
C) Slugs And Tillage

A) Reminders On Wheat Herbicides - Mark Loux CORN Questions

With most of the wheat in the state in Feekes stage 5 or less, all herbicides labeled can be safely used still. As wheat reaches jointing or Feekes stage 6, all Banvel products and most 2,4-D products should no longer be used. Some 2,4-D product labels allow application through early boot, and past experience indicates use of lower rates of 2,4-D to be safe before early boot. We would suggest being cautious about herbicide use during the current spell of cold weather, and delaying application until warmer weather resumes if possible. Weeds do not respond well to herbicides under cold conditions, and wheat may be more sensitive to injury from herbicides.

B)Winter Wheat Growth Rapid, Tiller Development Good, Cold Weather Should Cause Little Problems - Pat Lipps CORN Questions

The warm temperatures and precipitation over the last week and a half have favored the rapid growth and development of the wheat crop in Ohio. Wheat in northern Ohio is in Feekes' growth stage 4 to 5 when the leaf sheaths begin to become erect. Early planted fields in southern Ohio are in growth stage 5 and some will likely be in growth stage 6 (first node visible) by the weekend. Each wheat plant now consists of a number of tillers. Wheat plants will continue to develop new tillers until the stems begin to elongate (growth stage 6) or day length exceeds 14 hours. Thus, tillering is just about complete. Tillers with at least three leaves have the potential to develop heads, but the actual number of heads produced per plant will depend on weather conditions in late April and early May and the level of fertility.

There have been only a few disease problems noted so far. Some fields have been diagnosed with wheat soilborne mosaic. This is a virus disease that causes severe stunting and yellowing of the plants. It usually occurs in patches in the field, mostly associated with wet areas or poorly drained soil types. Some varieties are susceptible and remain stunted into late spring, where others are resistant and show no signs of the disease. Check fields now that have not shown significant regrowth for the possibility of wheat soilborne mosaic. Some fields in northern Ohio have suffered plant loss from heaving and some root disease problems which made the plants sensitive to cold injury over winter. Affected areas have dead plants in patches. The root disease causes the crowns and subcrown internode (the structure connecting the seed with the crown) to turn brown. We expect any of these plants that are not already died, to die over the next few weeks.

The colder weather that is predicted for this week should have little effect on the wheat crop other than the possibility of causing some frost injury on leaf tips. Wheat in the tillering growth stages (GS 4 and 5) can tolerate temperatures down to 12 degrees F for a few hours with just some leaf tip burn (necrosis). Plants at the jointing stage (growth stage 6) may be injured at temperatures of 24 degrees F or below. Plants in the jointing stage have the growing point several inches above the soil surface. Freezing injury may cause the growing point to die and leaves to turn yellow or brown. Most of our wheat crop is not this far advanced, so injury should be minimal if we reach the predicted low temperatures.

C) Slugs And Tillage - Ron Hammond CORN Questions

Growers should realize that tillage continues to be an option for management of slugs in corn and soybean fields. Tillage helps to lower the potential for damage because it removes the residue which provides a favorable slug habitat, and also assists by warming and drying the soil to encourage more rapid plant growth. However, the use of tillage has to be weighed against the benefits of no-tillage production practices.

Tilling for slug management would be considered a preventive tactic, done before knowing a problem actually exists. The previous history of slug problems within a field including stand reductions, the relative size of the slug population in the fall of 2000, and sampling of slugs this spring should be considered in deciding whether tillage should be done. Economically, using tillage should be less costly than a molluscicide treatment at planting time.

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: Steve Prochaska        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 |