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Agronomic Crops Network

Ohio State University Extension


C.O.R.N. Newsletter 2011-28

Dates Covered: 
August 23, 2011 - August 30, 2011
Rob Leeds

Next two weeks: Near normal temperatures, Below normal rainfall

Near normal temperatures and below normal rainfall is expected the during these next two weeks (August 23-September 6). Hurricane Irene will move up the East Coast this weekend which will enhance drying in the Ohio Valley including Ohio and Indiana. Before that we will see some rain late Wednesday (August 24) into early Thursday this week with a front. The heaviest rain will be in the far north and northwest section with 0.5-1.0 inches expected there. Elsewhere it should be less. A few weak systems will move through next week with minimal rains.

Looking ahead it still looks to be a slightly warmer autumn with drier than normal weather gradually turning wetter but likely not before November or December.

Some climate models indicate another La Nina this winter and next spring. If that happens we could expect another cool and damp planting season next spring. We will update you on this as confidence grows the next few months.

We will take a look at the prospect for frost this fall in next week's report.

Late Maturing Soybeans and Aphids

Late Maturing Soybeans and Aphids

Now that soybean aphids have reached economic thresholds in parts of the state (an average of 250 aphids per plant), the main question being asked is how long a grower should be concerned about treating soybean fields, being that it is already the second half of August.   In most years, we would be getting into the later part of the soybean growth cycle, with plants in late R5 and R6 where the beans are mostly filled.  However, because of the late planting over most of Ohio, most fields are still in late R4 and early R5, some even with flowers, and thus, there are 2-4 weeks of continued growth and pod fill.  Research suggests that aphids can continue to cause economic losses into the R6 growth stage.  Thus in terms of crop susceptibility, soybeans will remain at risk for while.

The question is how long soybean aphids will continue to develop populations on the crop and rise in numbers to the economic threshold, prior to developing populations that will migrate to buckthorn to overwinter.  Many things probably affect when that will happen, including temperature, day length, and the stage of plant growth.  How all these variables will interact in Ohio remains to be seen.  However, because 1) soybeans will remain susceptible until early September and 2) aphids have the potential to continue their growth and development on soybeans, we recommend that growers continue to scout for this pest and treat if necessary.   The 250 aphid per plant threshold should be used at R5 if aphid levels are still rising and in early R6 if the plants are also under stress.

Wheat fungicide seed treatment

Fungicide seed treatments may play an important role in giving seedlings a good head start by protecting them from early-season diseases caused by Fusarium, Pythium, and Rhizoctonia species. In addition, seed fungicide treatments may also prevent early establishment of diseases such as Stagonospora blotch and minimize problems with loose smut and common bunt. Seed treatments are most beneficial for seeds infected prior to planting or when seeds are planted under cool, wet soil conditions. However, seed treatments should not be considered a cure-all for the selection of poor seed lots. They will not increase the germination of poor quality seeds – seeds with excessive mechanical damage, seeds stored under poor conditions, genetic differences in variety, or other damage.

In general, seed treatments result in increased yield by minimizing stand reduction resulting from infection and death of seedlings caused soil borne pathogens. However, seed treatments do not always increase yield. Moreover, protection is also short-lived, generally only lasting as long as it takes for the crop to emerge. In addition, no single seed treatment or active ingredient is equally effective against all soil borne pathogens or all populations of the same pathogen. Therefore, producers should select seed treatment based on potential seed and seedling disease problems and the history of such problems in their fields. For instance, avoid planting seeds harvested from scab-infected fields, but if scabby seeds are used for planting, then a fungicide with activity against Fusarium should be selected. On the other hand, if a field has a history of Pythium damping off due to cool, wet planting conditions, a seed treatment product with activity against Pythium should be selected.

It is highly recommended that winter wheat seeds be treated for control of several seed-borne diseases, including loose smut, common bunt, Stagonospora glume blotch and scab. The systemic fungicides Dividend Extreme and Raxil - Thiram, and Raxil XT have excellent activity against both loose smut and common bunt at low usage rates (a.i./ cwt). Dividend Extreme is effective in controlling seed-borne Stagonospora, but it is more effective against seed-borne scab at the higher rate (1.0 fl. oz./cwt) than at the lower rate (0.5 fl. oz./cwt). In general, triazole-based fungicide such as Raxil and Charter, used at the labeled rates, are effective against seed-borne Stagonospora and have relatively good activity against seed-borne scab. Products with Metalaxyl and Mefenoxam are effective against Pythium. For best results and protection against a wide range of pathogens, seeds should be treated with multiple active ingredients.

Visit the field crops disease website for more on wheat seed treatment:

Yield Monitor Calibration Tips - Time is Money!!!

GPS-based yield data has proven to be an extremely valuable management tool on many Ohio farms. However, improperly calibrated yield monitors can essentially generate difficult to interpret or useless data … Garbage In = Garbage Out.

Economic risk in agriculture has increased dramatically. Considering the amount of economic risk involved in each decision, taking the time and patience to properly calibrate a yield monitor is essential if the yield data will be used to make future agronomic decisions for your farming operation.

Most yield monitors operate on the same basic principles. Yield monitor manufacturers strive to build accuracy into their units; however, each machine has its sources of errors. Proper calibration requires harvesting 3 to 5 separate calibration loads. Each load should represent different flow rates. This can be easily accomplished by harvesting at different speeds (i.e. 3 mph, 3.5 mph, 4 mph, 4.5 mph, 5 mph, etc.) The different flow rates represent different yield levels to the yield monitor. Additionally most manufacturers recommend that the calibration load weigh between 3,000 to 6,000 pounds, approximately 50 - 100 bushels. Each load should be individually weighed in a weigh wagon or other accurate scales. If one load appears to be uncharacteristically high or low, redo that load before completing the calibration.

Check the accuracy of your yield monitor throughout the harvest season. To insure consistent data additional calibrations may be necessary. Multiple calibrations are essential in higher moisture grain. For example corn at 25% moisture moves through a combine much differently than corn at 17% moisture.

Other important tasks:

- Calibrate for each grain type.

- Calibrate grain moisture sensor

- Calibrate temperature sensor

See the following yield monitor checklist for more tips.

Yield Monitor Checklist

Before Operation

- If you have not already done so, back up any data from the previous season on the memory cards, thumb drives, monitors, etc., After the previous harvest data is backed up delete the files from the memory devices. It is good practice to keep several back up copies of the raw data in different locations in case it is lost, stolen, damaged or modified.

- Check your memory card, thumb drive, etc., to be sure they work properly.

- Contact your local dealer or manufacturer to make sure that you have the recent software and firmware upgrades for your yield monitoring and mapping system. You can obtain information about these upgrades through your manufacturer's web site or by contacting technical support.

- Check all cables, connections, and sensors for wear or damage from rodents.

- For elevator-mounted moisture sensor units make sure the grain is cleaned out and the manual clean-out motor works and all doors are shut!

- Inspect the flow sensor. Look for wear on the grain elevator and missing or worn paddles. Check to make sure that the spacing between the paddles and the top of the elevator meets the manufacturer's requirements.

- Look for wear on the flow sensor's impact or deflector plates and replace if plates appear worn.

- If you purchase a new or used combine with an existing yield monitor installed double check to make sure it is installed properly.

- Avoid running electrical wires next to the GPS antenna which may cause interference with the receiver signal. Running wires perpendicular to each other decreases the chance for electrical noise that may occur from other electronics.

During Operation, Prior To Calibration

- Make sure your memory card, thumb drive, etc., is installed into your yield monitor and turn on your combine and yield monitor. Make sure there is proper communication between the card and the display monitor. Usually an error message will appear on the display indicating there is no communication with the card.

- Check to see if you are receiving a good differential correction signal (DGPS).

- Raise and lower the header to make sure the stop height switch operates correctly. Some monitors are equipped with a manual switch which turns on and off data collection to your monitor. You may have to adjust the header height switch to accommodate the preferences of different operators during harvest.

- Make sure to set row width according to number of rows for a row crop header and the appropriate width of a cutting platform header.

- Engage the separator and observe the elevator speed on the monitor to see if it is working.

- Put the combine in drive and make sure the ground speed indicator is working.

- Before calibrating loads make sure you will be using accurate scales to weigh the grain. Certified scales or calibrated weigh wagons are recommended. If you are using weigh wagons it is recommended to leave the wagon in one location in the field. Moving the weigh wagon through a field causes it to shake and bounce which can throw off the calibration of the weigh wagon. Make sure you are also using the same scales throughout calibration.

During Calibration

- When collecting temperature readings of the equipment for some yield monitors make sure the combine has been out in normal operating temperatures for several hours. For example, taking a temperature reading from the combine when it has been in the shed or under a shade tree is much different than under direct sunlight. Take temperature readings close to the moisture sensor on the combine.

- Collect moisture calibrations for each grain type. Take a good representation of the moisture of the grain harvested throughout the loads.

- When calibrating monitor for ground speeds use typical field conditions rather than a road or waterway. Tire slippage can create inaccuracy with calibration.

- Harvest calibration loads at different flow rates. Yield will vary throughout the field. Adjusting flow rates will improve accuracy. When calibrating loads it is recommended to use loads between 3,000 to 6,000 pounds. This helps reduce variability with excess grain that may be in the combine. - Gather loads in well represented areas of the field. Avoid starting calibration loads on turn rows, weed patches, or areas of major topography changes in the field. Hillsides and rolling ground can impact calibration load data because of how the grain impacts the flow sensor. If you are unable to avoid topographical changes make sure you get a good representation of loads going up-and-down hill and side-to-side of a hill.

- It is recommended to calibrate for each type of grain for each year. The dynamics of the combine changes from wear and tear and can influence the outcome of your yield data.

- When conducting on-farm research trials or harvesting fields with multiple varieties consider creating a calibration load for each treatment or variety. For example, calibrate for regular corn and high oil corn separately due to the differences in test weight and moisture characteristics of the grain.

- Calibrate for different moisture levels per type of grain. For example, calibrate differently for corn below 22% moisture versus corn above 22% moisture.

During Harvest

- Correct any malfunctions or errors indicated by the yield monitor. This can include moisture and flow sensors not working properly and loss of DGPS signal. Make sure the monitor is actually collecting data. Sometimes one can manually switch off data collection on the monitor and forget to turn it back on.

- If you have a long harvest season it would be wise to do periodic calibration loads throughout the season to check or improve accuracy. It is suggested to recalibrate if you see more than a 5 percent difference in error, 5 lb/bushel differences in test weight, or temperature changes greater than 10 degrees.

- It is recommended to back-up data onto your computer and data storage devices frequently throughout the harvest season. A simple electrical shock form improper wiring or lightning can destroy your data.

- If significant changes are made to the elevator chain, paddles, or flow sensor during harvest you will need to recalibrate. Tightening the elevator chain, replacing old paddles or changing the gap of the flow sensor to the paddles changes the outcome of the previous calibration.

- If you run into problems with the monitoring equipment during harvest check through the trouble shooting information in the operators manual. Contact technical support if you are unable to solve the problem.

Northern Ohio Wheat Day - Sept. 7

Northern Ohio Wheat Day - Sept. 7

A meeting for farmers, seed dealers, fertilizer and chemical dealers, and milling industry personnel has been scheduled for Sept. 7 in Fostoria, Ohio. This meeting will be co-hosted by the Mennel Milling Company and will be held at St. Wendalin Parish Hall, 323 N. Wood Street. There will be no charge for the program, but to get a lunch count, please rsvp to by Sept. 5.

The primary purpose of the meeting will be to address with current research (from OSU and other mid-west land grant universities), the following wheat cultural issues:

1. Fusarium Head Scab Management

2. Fungicide efficacy on wheat disease as it relates to timing, coverage, and active ingredients.

3. Wheat fertility

4. Wheat variety development

5. Wheat row spacing (7.5 and 15 inch)

6. Value of wheat to rotation, double cropping, modified relay intercropping, etc.

7. An Ohio Corn and Wheat Association update on wheat and information about the strategic plan being developed for wheat.

In addition to the above agronomic components to the program, there will be an opportunity to visit the Mennel wheat research laboratory and learn about their wheat research focus. For a complete program review and speakers, go to

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Crop Observation and Recommendation Network

C.O.R.N. Newsletter is a summary of crop observations, related information, and appropriate recommendations for Ohio crop producers and industry. C.O.R.N. Newsletter is produced by the Ohio State University Extension Agronomy Team, state specialists at The Ohio State University and the Ohio Agricultural Research and Development Center (OARDC). C.O.R.N. Newsletter questions are directed to Extension and OARDC state specialists and associates at Ohio State.