http://www.ag.ohio-state.edu/~corn/

CORN
Crop Observation and Recommendation Network

2001-32
C.O.R.N. September 24 to September 30, 2001

In This Issue:

A) Wheat Fertility Guidelines
B) Soybean Cyst Nematode It did not go away!
C) Farm Security Is Important
D) Time and Temperature Effects on Herbicides
E) Stored Grain Insect Control

 

A) Wheat Fertility Guidelines (Beuerlein) CORN Questions

The results of several research projects indicate that the application of 25 pounds of nitrogen at planting will increase fall growth, tillering, winter hardiness and grain yield. Most forms of nitrogen are satisfactory and incorporation into the soil is not necessary.

Wheat requires at least 45ppm of available phosphorus per acre in the soil to produce really good grain yields. If a soil test indicates less than 40 ppm, then apply 80 100 pounds P2O5 at planting and incorporate to a shallow depth.

Soil potassium should be maintained at levels of 135, 165, and 185 ppm for soils with cation exchange capacities of 10, 20 or 30, respectively. If potassium levels are low, apply 60 100 pounds of K2O and incorporate to a shallow depth.

In Ohio, limed soils usually have adequate calcium, magnesium and sulfur for wheat. Soil pH should be between 6.5 and 7.0. Soil pH values lower than 6.0 are usually detrimental to grain yield.

 

B) Soybean Cyst Nematode It did not go away! (Anne Dorrance) CORN Questions

Soybean cyst nematode is still a pest in many of Ohio's production fields http://www.ag.ohio-state.edu/~ipm/scn/scn2.htm. Thanks to the soil survey sponsored by he Ohio Soybean Council, we know some of the fields that are infested with SCN. This nematode pest, feeds on the roots and the plant sends foods to the growing syst instead of to the beans.

Light infestations of SCN in fields will have no above ground symptoms, which is part of the challenge, but yields will be anywhere from 5 to 10 bushels off of your neighbors fields with a similar soil type. Higher infestations on susceptible soybean cultivars will have more severe symptoms, such as: beans will be irregular in eight, mixtures of tall and short beans, early yellowing and very low yields. We manage this pest with crop rotation which reduces the SCN population levels and planting resistant cultivars. However, SCN readily adapts to ALL sources of resistance so it is important to manage the type of resistance that we plant in a field.

When should you sample fields, this depends on several things.

  1. Has the field ever been sampled? You are way behind the eight ball on this one. SCN is most commonly spread on equipment, but also by flooding water, soil peds in seed, anything that moves soil. With the numbers of fields that have SCN, it is likely that most fields in the state have some level of SCN.

  2. SCN not detected in earlier survey? SCN exists in fields in pockets, so be aware that a periodic sampling is still necessary. SCN levels could have been very low and not detectable in the earlier surveys. If you have a good 3 crop rotation, probably sampling every 10 years is adequate. If you are in a continuous soybean production, sampling every 3 years for fields where it was never detected before is more appropriate

  3. SCN was detected now in a rotation scheme. The best time to sample for SCN fields is the year prior to planting soybeans. One caution is if you are using the same source of resistance over and over (which you shouldn't do) is to sample after soybean harvest. If the SCN populations increase after planting a resistant variety it's time to add another non host year in the rotation (include wheat or alfalfa in the rotation or add another year of corn) and change to a new source of resistance the year that soybeans go into the rotation.

How to sample:

The best time to sample fields for soybean cyst nematode is in the fall after the soybeans are harvested. Soybean cyst nematode populations can increase as much as 10 to 30 fold per growing season so early soil sampling may give lower numbers. Soybean cyst nematodes will not be distributed evenly throughout a field. techniques for sampling soil for SCN by the Soybean Cyst Nematode Coalition are as follows:

  1. Use a one inch diameter soil probe to collect samples (6 8 inches in depth)
  2. Following a zig zag pattern, collect 10 to 20 soil cores per 10 to 20 acres
  3. Collect cores from areas of similar soil type and crop history
  4. Dump cores from each 10 to 20 acre area into a bucket or tub and mixthoroughly
  5. Place 1 pint (2 cups) of mixed soil in a soil sample bag or plastic zippered bag and label with a permanent marker; and
  6. Store sample in cool, dark place until shipped to lab doing SCN analysis.

This level of sampling is necessary to obtain relatively accurate counts of the nematode population and to make meaningful recommendations for management. Charges this year are $15.00 for the first sample and $10.00 for each additional sample per shipment. Forms to accompany samples can found at the county extension offices or http://www.ag.ohio-state.edu/~plantdoc/cweppdc/scnform.html

Mail samples to:
C. Wayne Ellett Plant & Pest Diagnostic Clinic
Room 110, Kottman Hall
2021 Coffey Road
The Ohio State University
Columbus, OH 43210

For more information on SCN in Ohio, yield losses associated with SCN, The SCN coalition Management guide see the following:

http://www.ag.ohio-state.edu/~ipm/scn/scn.htm

 

C) Security Is Important (Joanne Kick Raack and Cindy Folck) CORN Questions

In the weeks following September 11, agriculture aerial applications were grounded after the FBI discovered that terrorists involved in the hijacking had also visited small, rural airfields to obtain information on crop dusting airplanes and equipment. Security experts were concerned the equipment could be misused for releasing biological or chemical agents, according to news reports.

Taking measures to keep pesticides secure to avoid misuse or vandalism takes on new meaning in light of these events. The following security measures should be taken with pesticides at anytime:

Pesticides should be stored in a locked building or cabinet that can't be accessed by children or people not associated with the farm. This also extends to commercial agriculture businesses.

Vehicles used to transport or apply pesticides should be kept locked.

Sprayer tanks should be empty when left unattended in a field or barnyard area. In previous years, vandals have targeted pesticides left in sprayer tanks overnight in parking lots and open areas.

Spraying of pesticides according to the label is not the security issue. Only the licensed applicator or supervised employees and family members should use pesticides. The concern is theft or vandalism of pesticides and applicator equipment. Keeping pesticides secured is important on the farm or in the commercial agriculture business.

 

D) Time and Temperature Effects on Herbicides (Stachler and Loux) CORN Questions

As you make herbicide treatments this fall, keep in mind that the temperature and time of day of the herbicide application can have an effect on herbicide performance. Based upon research conducted this past summer at OSU, herbicide applications made from dusk until dawn showed poorer weed control compared to after dawn and before dusk. Therefore we recommend herbicide applications be made during daylight hours, especially if the weeds are under stress. More details will be revealed in a future C.O.R.N. newsletter.

For control of warm season weeds, such as hemp dogbane, johnsongrass, and milkweed, herbicide applications should be made during periods of warm weather (daytime in 70's and nighttime above 45 or 50 degrees). For control of cool season weeds, such as quackgrass, Canada thistle, dandelion, common chickweed, or purple deadnettle, make herbicide applications when the morning low is greater than 35 degrees and daytime temperatures are as warm as
possible (at least 50 degrees). It is best to have similar temperatures the day before and after the herbicide application. These are rough guidelines to follow in order to maximize weed control.

 

E) Stored Grain Insect Control (Adapted from materials by Curtis Young) CORN Questions

As we move into harvest, many bins may still need attention to get them ready for filling. The following are lists of insecticides that may be used as empty bin treatments or as grain protectants. The list is ever changing due to label changes. Remember to read the label carefully prior to purchase and application.

Empty Bin Treatments

Grain Protectants

For more information on grain bin pest control, refer to Extension Bulletin 153, "Stored Grain Insect Control" available at your local Extension Office and online at our Ohioline website:
http://ohioline.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: Anne Dorrance and Dennis Mills (Plant Pathology), Ron Hammond and Bruce Eisley (Entomology), Jeff Stachler and Mark Loux (Weed Science), Jim Beuerlein (Hort & Crop Science, Soybean & Small Grain Production), Joanne Kick Raack and Cindy Folck (Pesticide Applicator Training),
Curtis Young (IPM) Extension Agents: Glen Arnold (Putnam), Clark Hutson (Seneca), Ray Wells (Ross), Roger Bender (Shelby), Barry Ward (Champaign)

Editor: Barry Ward        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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