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7/9/2012 - 7/15/2012

Insurance Coverage for Drought-Damaged Crops

By William Edwards, Department of Economics

Nearly 90 percent of the corn and soybean acres in Iowa are covered by multiple peril crop insurance. Drought damage is an insurable loss under these policies. Producers should consult with their crop insurance agents before harvesting or destroying any drought-damaged crops, however. 

The agent will notify a certified crop adjustor to appraise the insured crops. Keep in mind that when damage is widespread, adjustors cannot be everywhere at once. The adjustor may declare the crop a complete loss. If it has significant yield potential, it can be left and harvested in the fall. If the producer elects to harvest it early, as silage, check strips can be left to verify the actual yield achieved. In any case, the acres must be released by the insurance company before the crop can be harvested early or destroyed.

Any insurance indemnity payments will be settled based on actual harvested production over the entire insurance unit. Fields declared a complete loss will be combined with any harvested acres in the same insurance unit to calculate the final yield. Yield losses are equal to the farm’s historical yield times the level of guarantee purchased, minus the actual yield.

Ninety percent of the insured acres in Iowa are covered by Revenue Protection insurance policies in 2012. Yield losses will be paid at a rate equal to the average CME futures price during the month of October, if it exceeds the average February price of $5.68 for corn (December contract) or $12.55 for soybeans (November contract). 

Following harvest, the usual evidence of actual production should be collected and submitted to the crop insurance agent as soon as possible if it appears that a payment is likely, but not later than 15 days after the end of the insurance period, which is Dec. 10 for corn and soybeans in Iowa. If a producer has a history of selling more than half the crop in the tax year following harvest, reporting of crop insurance proceeds can be deferred to the next tax year.

More information about crop insurance policies and procedures can be found on the Ag Decision Maker website.


William Edwards is an Iowa State University professor of economics with extension responsibilities in farm business management. Edwards can be contacted at 515-294-6161 or by emailing

Changes in Pesticide Applicator Certification and Licenses

By Kristine Schaefer, Department of Entomology, and Gretchen Paluch, Iowa Department of Agriculture and Land Stewardship

The Iowa Legislature recently passed changes to the Iowa Code that will affect commercial, public, and private pesticide applicators.  Previously, commercial, public, and private applicators had the option of paying one-year or three-year certification fees. Effective July 1, 2012, one-year certification fees are no longer available. All individual pesticide applicator certification fees will now cover three years.  Certified pesticide applicators that currently pay one-year fees but are in a three-year qualification cycle will be eligible to pay the one-year certification renewal fee until the existing cycle expiration date. 

Another change that took effect July 1, 2012 concerns evidence of financial responsibility for commercial pesticide applicator businesses. To be issued a license, commercial pesticide applicator licensees (businesses) will be required to provide proof of financial responsibility for a minimum amount of $250,000 for property damage and $250,000 for public liability, each separately. Certificates of insurance meeting the $250,000 minimum requirements will be required to renew commercial pesticide applicator licenses for 2013. Certificates of insurance issued prior to July 1, 2012, will expire on December 31, 2012. 

For additional information refer to the IDALS Pesticide Bureau website or call 515-281-8591 for private pesticide applicator information and 515-281-5601 for commercial pesticide applicator information.


Kristine Schaefer is a program specialist in the Department of Entomology. She can be reached at 515-294-4286 or e-mail Gretchen Paluch is pesticide bureau chief for the Iowa Department of Agriculture and Land Stewardship.  She can be reached at 515-281-8590 or e-mail

Alternatives for Drought-damaged Soybeans – Bean Crop or Forage

By Stephen Barnhart and Andy Lenssen, Department of Agronomy    

As people reflect on the reasons for the irregular development and poor soybean production in Iowa this year, the next important questions relate to evaluation of crops in individual fields and planning when and how to harvest them to the greatest economic advantage. This evaluation involves reviewing normal crop growth and development, assessing the condition of the crops in individual fields relative to normal and to think through several harvest scenarios. Will this field have a harvestable soybean crop? Are there concerns about the crops? What use or management alternatives do I have?

Soybeans are primarily grown for oil and protein in the Midwest.   However, soybeans were first introduced to the United States as a forage crop and still have that potential. In a season such as this, when poor establishment and drought stress may have limited the potential as a bean crop, when is it appropriate to abandon hope of profitable grain yield from a soybean crop and look to it as a possible forage source? The critical decision should be based on whether it will produce an economic bean yield

Iowa research shows that 100,000 to 125,000 soybean plants per acre at harvest typically produces 95 percent or  more of maximum yield. At lower plant populations, soybean plants compensate with increased branching, producing more pods per plant. Bean yields remain relatively constant until populations drop below about 64,000 plants per acre at harvest. Bean yield estimate methods have been developed for stands about three weeks prior to combine harvest,  so their usefulness is of limited value when drought-stressed soybeans are being assessed in mid-summer for harvest as beans or as forage.


Soybeans as a forage crop

If the decision is made to abandon a bean crop and instead harvest the soybeans as forage, the decision should be made before the soybean plants reach developmental stage R6 (full green bean stage). Soybean forage may be more valuable in a dry growing season when traditional hay production is limited. 


What is the quality of soybean forage?

When in vegetative and early grain development stages, the soybean plant is very similar in feeding value and harvestable yield to that of more familiar forage legumes such as alfalfa or red clover.  As with other forage plants, the developing stem becomes less digestible while the leaves, and in the case of the soybean, the pods and developing seed remain highly digestible. Data presented in Table 1 shows relative yields and nutritive characteristics of whole plant soybean forage at increasing stages of development.  Note that while the protein and digestibility remain surprisingly constant over this range of harvest periods, the harvestable dry matter increases with maturity.  Beyond R6, however, the leaf material will quickly be lost, leaving a forage material with a high proportion of high quality pods with beans and the remainder being very low quality, high fiber stems. The risk of pod and bean shatter loss also increases if soybeans are harvested much past R6. The feed value of soybean stems alone is lower than that of corn stover. However, the feed value of soybean hay containing leaves and mature pods is greater.



Managing soybeans for dry hay  

Immature soybeans will have some of the same field curing challenges as other forage legumes, primarily due to stems drying more slowly than leaves. Soybean leaves become brittle when dry and can shatter excessively during raking and baling. While the use of a mechanical conditioner will speed the drying of stems, producers have found that flail conditioners lead to more leaf and pod losses than roller-type conditioners. If windrows are raked, it should be done when relative humidity levels are higher and leaves have absorbed some moisture, conditions that occur during early morning, late evening or nighttime hours. Soybean hay bales are subject to more rain and weathering loss if stored outside than are those of grass or alfalfa hay, so inside or covered storage is recommended.


Managing soybeans for silage

Producing good soybean silage requires techniques more similar to those used for silage produced from alfalfa than for silage produced from corn.  Better feed value retention from soybean dry matter will occur if soybeans can be stored as silage than hay. The target range for moisture content when ensiling soybean is 60 to 65 percent, so green plants cut for silage may require some field wilting before chopping. Drying conditions will dictate how long the wilt period should be. If wilted too long, the silage will be more difficult to pack, and you increase the risk of increased dry matter loss from excessive respiration and heating during ensiling. Excessively dry haylage may represent a fire hazard.

Soybeans chopped and stored at higher than 70 percent moisture may undergo abnormal or incomplete fermentation and will begin to lose dry matter as seepage (effluent) losses. Use caution when locating a site for silage storage with potential for seepage losses because off-site movement of silage effluent can become an environmental hazard as a ground or surface water contamination source. High-moisture forage legumes, likely soybeans too, usually have lower concentrations of soluble carbohydrates than does chopped corn.  Adequate concentrations of soluble carbohydrates are necessary for rapid pH decrease during the ensiling process.

 It is difficult to estimate the moisture content of immature, standing soybeans. Sample several representative plants from the field and have moisture determinations made at a nearby feed testing laboratory. Alternatively, check plant moisture with a home check using an accurate scale and a microwave oven or heat lamp to dry the sample. Use caution when drying forage at home with a microwave oven or  heat lamp. As the plant material dries, it becomes more combustible. Special precautions should also be taken to avoid permanent damage to microwave ovens. 


A few additional cautions about using soybeans for forage

Review your fungicide and herbicide labels for any restrictions regarding preharvest intervals. Soybean forage being stored as silage often will ferment more favorably and attain a lower pH  if inoculated with a lactic acid bacteria inoculant applied at the chopper or at the silo. Several animal nutritionists say that very immature, green soybeans with only small pods and no appreciable bean formation can be fed as you would feed other legume forage. However, as the whole plant fat content increases with bean development, these nutritionists caution producers to limit the amounts fed daily to livestock. Check with a nutritionist when formulating rations containing soybean forage.


Stephen Barnhart is an extension forage agronomist. He can be reached at 515-294-7835 or e-mail Andy Lenssen is a soybeans systems agronomist. He can be reached at 515-294-1360 or e-mail

Alternatives for Drought-damaged Corn – Grain Crop or Forage

By Stephen Barnhart and Roger Elmore, Department of Agronomy

As people reflect on the reasons for the irregular development and poor grain production in Iowa this year, the next important questions relate to evaluation of crops in individual fields and planning when and how to harvest them to the greatest economic advantage. This evaluation involves reviewing normal crop growth and development, assessing the condition of the crops in individual fields relative to normal, and to think through several harvest scenarios such as: Will this field have a harvestable grain crop? Are there concerns about the crops? What use or management alternatives do I have?

Most of the Iowa corn crop is intended for harvest as dry grain. If it has sufficient grain content and quality, corn will be more valuable as harvested grain. If the field or parts of the field fall short of economic grain potential, some producers can harvest this low-yield corn for silage or use it in grazing programs.

Predicting grain yield mid-season is difficult. It involves assessing what you have in the field and comparing that with normal crop growth and development. With normal corn development, the number of pollinated kernels should be visible at about 10 to 12 days after silking (blister stage). This represents potential grain set. If weather conditions have adversely affected pollination, it will be evident at blister stage. For the remainder of the summer, weather conditions influence how many of these pollinated kernels develop and the stage of their development. Harvest decisions can then be based on knowledge of seed development gained by monitoring.

If the crop does not appear to be developing well, and you are making early forage harvest decisions, the following guidelines have been adapted from the University of Wisconsin Extension for estimating silage yield of moisture-stressed corn.


Grain yield method for estimating silage yield

For moisture-stressed corn, about 1 ton of silage per acre can be obtained for each 5 bushels of grain per acre. For example, if you expect a grain yield of 50 bushels per acre, you will get about 10 tons/acre of 70 percent moisture silage (3 tons/acre dry matter yield). For corn yielding more than 100 bushels per acre, about 1 ton of silage per acre can be expected for each 6 to 7 bushels of grain per acre. For example, for corn yielding 125 bushels of grain per acre, corn silage yields will be 18 to 20 tons per acre at 70 percent moisture (5 to 6 tons per acre dry matter yield).


Plant height method for estimating silage yield

If little or no grain is expected, a rough estimate of yield can be made assuming that 1 ton of 70 percent moisture silage can be obtained for each foot of plant height (excluding the tassel). For example, corn at 3 to 4 foot will produce about 3 to 4 tons per acre of silage at 70 percent moisture (about 1 ton per acre of dry matter).

In addition to yield, other factors also should be considered. Stage of development or condition of growth also has an influence on the feed value of the harvested crop. Compared to normal corn, corn that would yield about 20 to 40 bu/A would have about the same pound for pound feed value. Very poorly pollinated stalks with 0 to 20 bu/A yield potential would have about 80 to 90 percent the feeding value of normal corn. Short, barren stalks would have only about 70 to 80 percent the feed value of normal corn.

In what form will the corn be harvested and used? The three most practical options for using drought-damaged corn are green chopping, ensiling and storing as dry stover. Each system has some advantages and disadvantages. Producers should consider the fungicides, herbicides or insecticides used in their corn production.  Each of these products has a legal preharvest interval. Early harvest or grazing may violate these intervals. Growers should carefully check the label for any restrictions that may affect harvest or harvest timing.

Green chopping corn provides an immediate source of feed for dry lot or supplement on pasture. A disadvantage may be a potentially high level of nitrates in the drought-damaged, fresh forage. Producers are encouraged to have fresh chopped corn tested for nitrates at a nearby commercial feed testing laboratory if there is any concern about high levels.

Chopping corn for silage provides a less immediate feed source, but a form that can be stored and fed over a longer period of time. One of the main management challenges of harvesting drought-damaged corn for silage is cutting the plant at the proper moisture content for the type of silo structure in which the forage will be stored. Corn should be stored at 65 to 70 percent moisture in a bunker or trench silo and at 60 to 65 percent moisture in upright silos. In plants with at least some grain, the dry down rate of the grain will provide a rough guide for predicting whole plant moisture.

Plants with no grain but with some live green leaf tissue still evident will have surprisingly high moisture content (75 to 80 percent), too high for direct cut ensiling. In some cases even when all the visible leaves have turned brown, the whole plant moisture is still above 70 percent moisture. Plants that have actually died will lose moisture very quickly and could drop below 50 percent moisture in a short time, too low for best nutrient conservation as silage. 

An accurate moisture test from a representative field sample is an important piece of information needed to manage a corn crop for silage. It is difficult to estimate the whole-plant moisture content in the field. The best method may be to chop a representative area of the field with the silage chopper to be used and send the representative sample of chopped forage to a test lab for moisture determination.  Moisture determinations can be made at a nearby feed testing laboratory or with a home check using an accurate scale and a microwave oven or heat lamp to dry the sample. Use caution when drying forage in a microwave oven or under a lamp at home. As the plant material dries it becomes more combustible. Special precautions should also be taken to avoid permanent damage to microwave ovens. 

If nitrate concentrations are a concern in the chopped crop, ensiling can diminish the nitrate concentration by 30 to 50 percent. Good management would be to have the silage tested by a commercial feed testing laboratory, after ensiling, to estimate nitrate concentration and nutritive value for livestock.  

Harvesting drought-injured corn as silage will not be a good option for everyone. Making good silage from a normal corn crop requires some degree of skill and attention to detail. If you do not already have the harvest machinery, a silage storage structure in good condition, experience in making corn silage, and a well-defined plan for silage use, then making silage from drought-damaged corn may be a high risk venture.

Too often producers who are looking for a 'cheap way’ to salvage a crop as silage choose to store silage in a wide, low pile on the ground, possibly even bounded on each side by a row of large round hay bales. These piles may seem to be low cost initially, but spoilage and waste is often high and as a result the 'cost' per ton of usable, good quality silage is higher than expected.

Stacking or baling as dry corn stover  - Drought-damaged corn has dried quickly in many areas. Corn that has dried below 55 to 60 percent moisture is not a good material for ensiling. Rather, it should be considered for possible stacking or baling as dry corn stover. Timeliness is not quite as critical when harvesting stover. It should be dried to 20 percent moisture or less to avoid spoilage in storage and should be harvested before excessive leaf loss occurs. High nitrates can be a concern with stover. If you're concerned, have a nitrate test done on a representative sample. A few other suggestions are to store stover at a dry location near the site of feeding, and provide limited access to stover during feeding to stretch feed supplies and minimize feeding waste while allowing livestock to adapt to potentially high nitrate-concentration forage.


Stephen Barnhart is an extension forage agronomist. He can be reached at 515-294-7835 or e-mail Roger Elmore is an extension corn agronomist. He can be reached at 515-294-6655 or

Scout for Twospotted Spider Mites This Summer

By Erin Hodgson, Department of Entomology

As mentioned in an earlier ICM News article, twospotted spider mites are problematic in droughty years. We recommend scouting corn and soybean fields for mite infestations this year because they thrive in hot and dry conditions. Twospotted spider mites can aggregate at the field edges, especially if there are weeds surrounding the borders. Eventually they can disperse with the wind to develop a field-wide infestation. I encourage people to look at the edge rows first to see if mites can be found. If their presence is confirmed, then estimate populations throughout the field by walking a “Z” or “W” pattern.

A few places in Iowa and surrounding states have already reported heavy twospotted spider mite populations with prolonged feeding in soybean (Photos 1 and 2). The first reports of spider mites in Iowa corn have started this week.


Photos 1 and 2. Prolonged spider mite feeding in soybean can result in plant discoloration and leaf drop. Photos taken on July 6, 2012, in Richardson County, Nebraska by Tracy Cameron.


Exact treatment thresholds for spider mites in corn and soybean do not exist. Instead, the decision to treat should take into consideration how long the field has been infested, mite density including eggs, mite location on the plant, moisture conditions and plant appearance. A general guideline for soybean is to treat between R1-R5 (bloom through beginning seed set) when most plants have mites, and heavy stipling and leaf discoloration are apparent on lower leaves. Foliar insecticides are recommended in corn from R1-R4 (silking through dough stage) when most plants have mites at or around the ear leaf and 15-20 percent leaf discoloration.

Organophosphates are the recommended insecticidal chemistry to manage spider mites (e.g., chlorpyrifos or dimethoate). Follow label directions and pay attention to application guidelines and preharvest intervals. Remember these products do not kill eggs, so continue scouting after an application to evaluate product efficacy and residual. To improve application coverage, consider increasing the water volume to make contact with spider mites. Border treatments may also be a cost effective option if heavy spider mite populations are restricted to edge rows.

For more information, visit these websites:


Erin Hodgson is an assistant professor of entomology with extension and research responsibilities; contact at or phone 515-294-2847.

This article was published originally on 7/16/2012 The information contained within the article may or may not be up to date depending on when you are accessing the information.

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