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9/28/2009 - 10/4/2009

Weekly Crop and Weather Report - Sept. 28

By Doug Cooper, Extension Communications specialist

ISU Extension climatologist Elwynn Taylor, integrated pest management specialist Rich Pope and corn agronomist Roger Elmore are interview guests this week. Taylor says a light frost is possible, but no crop damage is expected. Pope reminds farmers that it's not too late to scout corn and soybean crops for weeds and insects. Elmore encourages corn farmers to pay close attention to poor standing crops as harvest gets underway.

Degree Days - The Finish Line Looms

By Rich Pope, Department of Plant Pathology

As of Sept. 27, 2009, we are close to winning the race between early frost and crop maturation across Iowa. The average date of first killing frost ranges from around Oct. 5 in central Iowa; about a week earlier to the north and west ,and a week later in southeast Iowa. It appears now that the 2009 first killing frost will occur at least at the average, and hopefully a bit later.

This good news is coupled with fairly favorable daily weather the last two to three weeks, with ample sunshine and mild evening temperatures. Reports from the field have both corn and soybean fields at or close to physiological maturity, with a few exceptions of late-planted or replant fields and other odd areas.

Degree day accumulation map for September 27, 2009

About six weeks ago, I posted a comparison of 2009 degree day accumulations through the season with other recent and notable years. As seen below, the favorable month of September is illustrated in the red line (2009). The red asterisk shows the line position as of September 27. Note that the last 3 to 4 weeks have led to a near-normal to slightly above normal temperature accumulations. Again, this is great news.

Degree day comparison with other years

Fall harvest is now just beginning in many areas.  As operators take to the field, a last check for pests while in the field is a great idea.  Because of the record cold July that limited vegetative growth and canopy fill in soybean, some weeds were allowed to flourish late in the season.

A final note that open, windy days can cause some lodging problems in corn fields, especially where stalk rots are developing. Scheduling corn harvest to take corn based on stalk strength monitoring can possibly net you a few extra bushels this year.

Stalk and ear rots are especially a concern in fields that were hail-damaged in July and August.  


Rich Pope is a program specialist with responsibilities with Integrated Pest Management. Pope can be contacted at or by calling (515) 294-5899.

Adjusting Hail-damaged Crops for Crop Insurance Reporting

By William Edwards, Department of Economics

Hail damage to crops in north central Iowa caused great losses; the total of which will become more defined with harvest. The following guidelines are intended to help farmers through the process of adjusting hail-damaged crops for crop insurance reporting.

Crop-hail and companion hail insurance

1. These are policies sold by private crop insurance companies. They are separate from the multiple peril policies regulated by the Risk Management Agency (USDA), and their premiums are not subsidized.
2. Crop-hail policies provide a maximum dollar amount of coverage per acre, with a fixed percent deductible. Companion hail policies are similar, but provide coverage only in addition to coverage provided by standard MPCI policies.
3. They generally cover damage due to hail, wind and/or fire. They do not cover yield loss due to other weather events, or price risk.
4. Damage is estimated as a percent of what the yield would have been without the weather occurrence, but a specific yield estimate is not made.
5. The adjustor may look at the crop soon after the damage occurs, but often will defer an appraisal until later, possibly just before harvest when crop damage is more evident. If the crop is harvested, check rows should be left.
6. After a percent loss is determined, the payment is equal to (percent loss minus percent deductible) x dollar value of coverage.
7. Many policies have a “disappearing deductible,” which means that as the percent crop loss increases the unpaid deductible portion decreases until eventually the entire loss is paid. This is done by multiplying the appraised loss by a factor of 1.25 or 1.5.

example 1


Multiple Peril Crop Insurance (MPCI)

1. The volume of crop is first corrected to a standard moisture percentage, 15 percent for corn and 13 percent for soybeans.
2. A quality adjustment factor is computed based on three factors:
• Sample grade discount of 9.9 percent. Additional discounts may be applied if a musty, sour or otherwise objectionable odor is detected.
• Low test weight, beginning at samples testing below 49 pounds per bushel for both corn and soybeans, and down to 46 pounds for corn or 44 pounds for soybeans.
• Excessive kernel damage, beginning at damage in excess of 10 percent for corn and 8 percent for soybeans, up to 35 percent kernel damage for either crop.
3. Quality discounts for damage in excess of the MPCI “chart values” for either low test weight or kernel damage will be based on the percent price discount determined by the buyer compared to the local market price on the same day. Unsold production will have an adjustment factor of 50 percent.
4. Additional discounts may be taken for substances such as aflatoxin, vomitoxin or fumonisin. Each substance has a separate discount table, ranging up to 40 percent for aflatoxin and fumonisin and 45 percent for vomitoxin. Samples tested for aflatoxin must be obtained before grain is placed into storage.
5. The bushels of production at the standard moisture level will be reduced by the percent quality adjustment factors to arrive at the “production to count” bushels. These bushels will be used to settle claims for any MPCI policy, and to calculate actual production history (APH) yields for future policies.

example 2

For more details consult your licensed crop insurance agent or insurance provider.

A related ICM News article, Update on Hail Damaged Grain, contains a short checklist for making decisions about crops affected by severe hailstorms.



William Edwards is a professor of economics with extension responsibilities in farm business management. Edwards can be contacted at (515) 294-6161 or by emailing

Update on Hail Damaged Grain

By Charles R. Hurburgh, Department Ag and Biosystems Engineering; Alison Robertson, Department of Plant Pathology

The situation with the hail damage to crops in north central Iowa is becoming clearer. On Aug. 9, 2009 an intense storm travelled approximately 150 miles from western Sac and Ida counties to eastern Grundy County. The hail swath was about ten miles wide, between Highways I-175 and US-20, with three miles in the middle being almost completely lost. The stones were large, which created major damage to both plants and developing grain. Earlier storms in northeast Iowa also created large losses but the grain itself was less developed.

For corn, the marketing concern is the mold damage created by bruising. Mold on standing corn is often accompanied by one or more mycotoxins. See and other information at Producers and grain handlers affected by the hailstorm can go through a short checklist to aid in making decisions.

1. Scout fields for damaged corn

• If  mold damage appears on more than 10 percent of kernels (approximately)

- Contact crop insurance first to determine what quality loss procedures apply.  Adjustment must be made in the field or immediately at harvest by the adjuster.  Timely adjustment is important for an accurate settlement.
- At harvest; if you are storing the corn temporarily or feeding the corn, take a composite sample per field (a pound or more per load). Test composite for toxins; work with nutritionist or veterinarian. Storage beyond the fall is not recommended.

• If mold damage appears on fewer than 10 percent of kernels, toxins may be present but are less likely. Storage and grading will still be issues.

2. Damage grading at local markets (elevator or processor) is difficult at harvest; and often is controversial.

• A two-probe sample should be taken per load, with only mechanical division (Boerner divider, etc.) to get the approximately 125 grams to be examined.
• Damage should be sorted on a wheat colored tabletop, with comparison to the USDA photographs.
• Discounted samples should be retained until the grain is settled.
• Use the local USDA-GIPSA service point (see list) to settle disputes, using the retained sample.  Periodically send some of the retained samples to GIPSA for comparison.
• If there is a question over the grade, sellers should raise it and ask for the Official test right away because samples do not keep.
• Even if average damage levels are not high enough to create discounts, keep daily composites of the inbound receipts, and grade them each day. This will allow inventory records to be accurate.
• If toxins are measured, a minimum of 5 pounds per sample is required. If a positive toxin test occurs, whether from a crop insurance adjustment, a market test, or a personal test, the corn must be used/marketed for use according to the FDA advisory levels.

3. Storage on-farm or at commercial markets

• Assign grain to storage by test weight; lighter corn will not store well, needs to be dryer and needs more aeration. Light corn should be the first sold; any corn less than 50 lb/bu is a very high storage risk, even in the winter.
• To determine average quality of the grain in a bin, use a combined sample of 1 pound or more taken per load.
• Cool and dry immediately, but expect more breakage in handling. Corn already moldy should be stored at 1-2 percent lower moisture than sound corn.
• Clean any corn known or suspected to contain toxins. This will likely reduce levels.  Three-sixteenths inch square mesh screens will take out most broken kernels. For high toxin levels, one-quarter inch mesh may have to be used, but some whole kernels will pass through. If the screenings are to be fed, get a complete toxin test first through a nutritionist or veterinarian.
• Remove center cores of bins. This will take out much of the remaining fine material.

Many of these recommendations are good grain management practice in any situation, but they are more important when quality has been deteriorated in the field.

For more information on this topic refer to the ICM News article on adjusting hail-damaged crops for crop insurance reporting written by William Edwards, extension economist.



Charles Hurburgh is a professor of Agricultural and Biosystems . He can be contacted at (515) 294- or by email at Alison Robertson is an assistant professor of plant pathology with research and extension responsibilities in field crop diseases. Robertson may be reached at (515) 294-6708 or by email at

This article was published originally on 10/5/2009 The information contained within the article may or may not be up to date depending on when you are accessing the information.

Links to this material are strongly encouraged. This article may be republished without further permission if it is published as written and includes credit to the author, Integrated Crop Management News and Iowa State University Extension. Prior permission from the author is required if this article is republished in any other manner.