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Ohio State University Extension

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C.O.R.N. Newsletter: 2016-33

  1. Tips for Harvesting Lodged Corn

    Author(s): Peter Thomison

    While never a recommended practice, this is definitely not the year to “store” corn in the field and delay harvest. Reports of lodging and downed corn are increasing across the state. Stalk rots are largely responsible for the problem which have been promoted by stressful production environments and susceptible hybrids. Affected corn stalks are characterized by internal plant tissue that has disintegrated and often appears “hollowed out”. These symptoms are also often present in the crown of the plant. Severe lodging slows the harvest operation causing delays that expose the crop to less favorable weather conditions, as well as wildlife damage.  Another loss may occur if ear rots develop when ears on lodged plants come in contact with wet soils and surface residues. Even certain hybrids that normally exhibit good standability and stalk quality are exhibiting significant lodging. According to some grower accounts, corn that had been standing well, collapsed in the course of a few days. In these extreme situations, growers may face major challenges harvesting lodged corn which is nearly flat on the ground.

    The following are tips from Dr. Mark Hanna, an extension agricultural engineer in agricultural and biosystems engineering at Iowa State University ( “Harvest tips for lodged corn”  http://crops.extension.iastate.edu/cropnews/2011/09/harvest-tips-lodged-corn)

     “Scout fields to determine where problem areas are and the condition of stalks and ears.  Harvest the problem areas first when field conditions are better and before kernels in close proximity to the ground have an opportunity for potential further deterioration. An exception might be made to harvest an area with particularly weak stalk strength that is still standing if the odds of lodging from weather seem high. 

    The only way to evaluate whether any harvesting aid or technique is helping is to measure harvest losses. Each ¾-pound ear on the ground per 436 square feet equals a loss of one bushel per acre.  Detailed instructions for measuring losses are in Profitable Corn Harvesting (https://store.extension.iastate.edu/Product/Profitable-Corn-Harvesting). Take a measuring tape to the field at harvest and spend a few minutes behind the combine checking losses. 

    Tips for machine operation to reduce losses

    • Set gathering chains for more aggressive operation with points opposite each other and relatively closer together. Adjust deck plates over snapping rolls only slightly wider than cornstalks so that they hold stalks but not so narrow that stalks wedge between the plates. 
    • Operate the head as low as practical without picking up rocks or significant amounts of soil.
    • Single-direction harvesting against the grain of leaning stalks may help. Evaluate losses though before spending large amounts of time dead-heading through the field.
    • Limited field measurements suggest a corn reel may or may not help limit machine losses; however, a reel likely allows greater travel speed and improves productivity.  Losses may be similar comparing harvest at 1 mile per hour without a reel and 3 miles per hour with a reel, but harvest goes much faster. Spiral cones mounted atop row dividers or the addition of higher dividers on each end of the cornhead are other potential after-market harvest aids.
    • If harvest speeds are significantly reduced, the amount of material going through the combine is reduced. Fan speed may need to be reduced to avoid blowing kernels out of the combine. Rotor speed may need to be reduced to maintain grain quality. Check kernel losses behind the combine and grain quality to fine tune cleaning and threshing adjustments. 
    • Grain platforms have been used to harvest corn in relatively severe cases. More cornstalks and material other than grain enters the combine. Expect capacity to be reduced somewhat. Concave clearance may need to be increased for increased throughput and fan speed may need to be increased to aid separation in the cleaning shoe…

    Perhaps as important as anything, get into the correct frame of mind and keep the right mental attitude. Recognize that speeds will be slower. Communicate these expectations with others. Don't allow an accident to compound harvest problems.”

    Several companies sell equipment for picking up lodged corn (http://extension.psu.edu/plants/crops/grains/corn/weather-related-corn-problems/corn-harvesting-equipment-for-wind-damaged-corn).

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  2. Open letter regarding efficacy of Cry1F trait on western bean cutworm

    This open letter was prepared by the undersigned entomologists and extension educators regarding the efficacy of the Cry1F (Herculex 1, TC1507) trait on western bean cutworm (Striacosta albicosta). We strongly urge seed companies to remove the designation of “control” from this toxin with regard to this pest.

    At the time Cry1F received regulatory approval in 2001, western bean cutworm was found in the far western Corn Belt (Colorado, Idaho, Nebraska, and Wyoming), with occasional movement into western Iowa. Indeed, EPA’s original Biopesticide Registration Action Document (BRAD) for Cry1F Bt corn, published in August 2001, did not even mention western bean cutworm. Instead, the following language was used: “The registrant-submitted data indicate that Cry1F protected corn offers excellent control of European corn borer, southwestern corn borer, fall armyworm, black cutworm, and suppression for the corn earworm.” References to Cry1F giving “excellent protection” against western bean cutworm began to appear in marketing literature only after Iowa State University entomologists documented its eastward range expansion and the first economic damage in that state. Presumably this rating was based on a limited number of lab assays and field trials done in pure Bt stands, not Refuge-in-a-Bag hybrids.

    The rapid eastward range expansion of western bean cutworm across the central Corn Belt into the Great Lakes Region resulted in a dramatic increase in the number of western bean cutworm-infested acres in a short time period. This created a large-scale ‘efficacy test’ of Cry1F hybrids to (as stated in the BRAD) “provide highly efficacious control of key Lepidopteran pests”, “reduce the use of more toxic chemical insecticides” and “reduce levels of mycotoxin in corn”. In all these regards, Cry1F has failed in our states. This season in particular, the level of larval infestation and damage is troubling in both single and pyramided Refuge-in-a-Bag hybrids from multiple seed companies. Wherever Cry1F is challenged by western bean cutworm, it fails to provide observable benefit to producers. We have collectively fielded dozens of phone calls and emails, and visited numerous fields; we know that our agribusiness contacts and seed industry agronomists have responded to many more, and corn acres were sprayed with both insecticides and fungicides (most too late and with little hope of benefit). People are frustrated and angry and, more importantly, yield was lost. Growers purchased Cry1F hybrids with the understanding that the trait provides “control”, thus negating the need to scout for egg masses or larvae in those fields. When the visible manifestations of damage became apparent late in the season, such as the intense ear-feeding we witnessed, it was far too late for rescue treatments. As the fall progresses and damaged corn is harvested, additional issues are sure to arise regarding quality and mycotoxin levels. The severity of the latter will largely be dependent on weather conditions favorable for ear mold development. What is certain is that many damaged ears are primed for fungal colonization and quality loss.

    As extension educators and specialists, we can no longer refer to Cry1F as providing western bean cutworm control. In fact the opposite is true, and our extension recommendations (including the Handy Bt Trait Table) will be changing to classify Cry1F hybrids for western bean cutworm the same as non-Bt, Cry1Ab, or double/ triple pro hybrids, all of which provide no control. In other words, we believe that Cry1F fields must be scouted for egg masses and sprayed with foliar insecticides if needed, the same as a non-Bt corn. Western bean cutworm is now the PRIMARY Lepidopteran ear pest in many parts of the Great Lakes region. For growers in our states, the costs of scouting and spraying Cry1F corn negates a major reason they purchased and planted a hybrid with the trait in the first place.

    Before growers make seed choices for 2017, we again urge the seed industry to acknowledge the reality of what is happening in the field, and to reclassify Cry1F in hybrid fact sheets, technical use agreements, and other educational materials. This would reduce grower expectations of Cry1F and allow local agricultural professionals to deal with their customers in a more truthful manner, in a way that allows for protection against yield loss. We also urge the industry to regard western bean as a primary, not a secondary, pest. Doing nothing risks alienating those close to the situation, including field agronomists, consultants, university extension staff and (most importantly) corn growers themselves who have a vested interest in finding effective pest management solutions for a growing world.

    Sincerely,

    Dr. Chris DiFonzo, Michigan State University
    Dr. Christian Krupke, Purdue University
    Dr. Andy Michel, The Ohio State University
    Dr. Elson Shields, Cornell University
    Dr. Kelley Tilmon, The Ohio State University
    Dr. John Tooker, Pennsylvania State University

    BRAD Document:  http://www.ceragmc.org/files/cera/GmCropDatabase/docs/decdocs/brad_006481.pdf)

  3. Brown Pods, Green Stems

    Last week, we received a few comments about soybeans having mature pods, but the stems remaining green. Similar observations were made in 2012…another dry year. Green stems on soybean may be a result of a source/sink problem. With the hot and dry conditions this year, pod set was likely reduced. With a limited number of pods (sink), there are fewer places for the plant’s photosynthates (source) to go.

    From previously conducted work by Dr. Jim Beuerlein, when soybean pods were removed from a plant node when they first formed and started to expand, the leaf at that node stayed green after the rest of the plant matured. If all the small pods were removed from a branch on a plant, that branch did not mature. Further, if setting of pods were prevented on the main stem of a plant but pods allowed to develop normally on the branches, those branches matured normally while the main stem stayed green and held onto its leaves. Anatomical studies of the flow of carbohydrates within a plant show that each leaf fills the pods at its node only, but if all its carbohydrates are not needed at that node, the extra will move to the next lower node. Therefore, soybean plants digest their leaves, petioles and stems to complete the pod filling process and add a few more bushels per acre. If the digestion of plant parts is not needed to complete pod fill, then these plant parts remain green.

    Another possible cause of stay green syndrome might be stink bug feeding. As the bugs feed, they inject saliva which may impact the plant’s physiology to remain green. In 2012, some acres of green stem were known to have stink bug infestations, especially along the edge. We have seen similar fields with stink bug pressure in 2016. To check for stink bug feeding, open a few pods and look for shriveled or flat seeds (see Figure for stink bug damaged seed) that may indicate stink bug feeding.

  4. 2017 On-Farm Fertilizer Trials for Corn, Soybean, and Wheat

    Ohio State is looking for farmer cooperators and crop consultants to help conduct on-farm field trials for the 2017 field season. The 2017 field season will likely be our last year of field trials before Ohio fertilizer recommendations are updated and/or revised. Updating fertilizer recommendations is a major undertaking that will require a collective effort from numerous OSU extension personnel, crop consultants and farmer cooperators. We are looking specifically at N, P, K and S in corn, soybean and wheat. We are collecting data from a large number of farms across the state and determine economically-optimum fertilization rates to maximize farmer profitability. These trials should be considered an opportunity to learn more about your farm’s fertility needs, but also contribute to a state-wide effort for better nutrient management and water quality outcomes.

    We can work either directly with farmers, or contract crop consultants and agronomists to conduct the trials and collect data on farmers’ fields. Farmers can choose which nutrient they’d like to work with and will have a large degree of flexibility in the plot layout and applied rates. We have funds to compensate both farmers and crop consultants for their time and effort.

    Phosphorus, Potassium, Sulfur Trials

    Experiments will involve either applying fertilizer or no fertilizer to replicated strip plots. Farmer can decide the rate and source of fertilizer. We are especially interested in fields that test low in P and K.

    Data to be collected:

    ·         Soil sample before planting

    ·         Leaf nutrient analysis at early reproductive stage (R1)

    ·         Grain yields at harvest and nutrient analysis of grain

    ·         Short questionnaire about soil management

    Nitrogen Rate Trials

    A full N rate will be applied in replicated strips. A zero N treatment is highly desired, but optional. Growers that include a fully replicated zero N treatment will be compensated extra to account for yield loss.

    Data to be collected:

    ·         Soil sample before planting

    ·         Leaf nutrient analysis at early reproductive stage (R1)

    ·         Corn stalk nitrate (optional)

    ·         Grain yields at harvest and nutrient analysis of grain

    ·         Short questionnaire about soil management

    For more information, please see go.osu.edu/fert-trials or contact Steve Culman at culman.2@osu.edu or (330) 822-3787.

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.

Contributors

Andy Michel (State Specialist, Entomology)
Bruce Clevenger, CCA (Field Specialist, Farm Management)
Elizabeth Hawkins (Field Specialist, Agronomic Systems)
Eric Richer, CCA (Field Specialist, Farm Management)
Glen Arnold, CCA (Field Specialist, Manure Nutrient Management )
Jason Hartschuh, CCA (Field Specialist, Dairy & Precision Livestock)
Laura Lindsey (State Specialist, Soybean and Small Grains)
Lee Beers, CCA (Educator, Agriculture and Natural Resources)
Les Ober, CCA (Educator, Agriculture and Natural Resources)
Mark Badertscher (Educator, Agriculture and Natural Resources)
Peter Thomison (State Specialist, Corn Production)
Pierce Paul (State Specialist, Corn and Wheat Diseases)
Sam Custer (Educator, Agriculture and Natural Resources)
Steve Culman (State Specialist, Soil Fertility)
Ted Wiseman (Educator, Agriculture and Natural Resources)

Disclaimer

The information presented here, along with any trade names used, is supplied with the understanding that no discrimination is intended and no endorsement is made 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.

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