Since 1961, Purdue's Entomology Department has been conducting the European corn borer (ECB) fall survey. Observations of both stalk damage and larvae attempting to overwinter are recorded for each of nine districts in the state. This data gives us a rough hindsight of ECB activity during the season and foresight of first-generation populations for the following year. Southern Indiana counties take-heart, we include southwestern corn borer in this survey.
BE A PART OF HISTORY! We need your help in locating and securing permission to enter some non-Bt cornfields in your area. We destroy up to 20 total plants/field, so the impact on yield will be minuscule. Besides non-Bt corn, we leave it up to you to decide what yellow-dent variety, planting date, tillage, etc that we inspect. Multiple fields to be sampled must be separated by several miles.
Data from individual fields will be shared with you. District and state data will be combined and shared with everyone in the October issue of the Pest&Crop. Because we are beginning this survey September 15, we request your field locations ASAP.
Please e-mail (firstname.lastname@example.org), call (765-494-4563), or FAX (765-494-2152) specific directions soon. Again, we need representation from ALL areas of Indiana. Thanks in advance!
One of the primary management practices to maintain quality is aeration. For aeration to be successful the grain has to be level and at moisture contents safe for storage because normal airflow in storage bins, silos, and flats is not enough to dry the grain. Go to www.ces.purdue.edu/extmedia/GQ/GQ-12.html for information on recommended maximum moisture contents for aerated grain storage in Indiana and the recommended airflow rates in upright and flat storages. Non-uniform temperatures in the grain bulk generate air currents that can lead to moisture migration when the stored grain is cooling.
Most storage problems result from improperly cooling the grain in the storage bin. The most common mistake is to stop running the aeration fan before the cooling front has moved through the entire grain pile. This can lead to condensation and crusted layers of spoiled grain in the bulk.
In the fall it may take up to two aeration cycles to cool the grain to below 45°F by mid November. At 0.1 cfm/bu it would require 150 hours per cycle regardless of grain depth. For winter storage in Indiana, the grain should be cooled below 35°F before the end of December.
The fan operation time depends solely on the airflow rate in the storage bin. An aeration fan is usually sized for about 1/10 cfm/bu, while an inbin drying fan is usually sized for 1 cfm/bu. It is very important to recognize the difference in order to operate the fans long enough to move the cooling front completely through the bulk, and yet not so long as to waste electricity.
Next week we will cover Pest Management Practices.
With all the hoopla about record or near-record Indiana corn yields this year, it may be prudent to recognize that late-season stresses will temper the high-yield excitement for some growers. As you read through this short list of fearmonger items, recognize that yield loss is a relative thing. Five or ten bushels lost from a 220 bu/ac potential still leaves you with very good yields and you may never realize that the yield loss occurred.
Just as importantly, many of the following stresses tend to increase the risk of stalk rots and weaker stalks by virtue of their negative effects on late-season photosynthetic capacity. A loss of photosynthetic capacity during the midst of grain fill can cause plants to remobilize carbohydrates stored in their stalk tissue to the developing grain. Such carbohydrate remobilization weakens the structural integrity of the stalks and increases the risk of subsequent stalk rot development. Growers should continue to inspect fields for compromised stalk strength or the development of severe stalk rots and adjust their harvest schedules accordingly.
Nafziger, Emerson. 2004. Toward the Finish Line. The Bulletin (Sep 2). Univ. of Illinois Extension. Online at www.ipm.uiuc.edu/bulletin/article.php?issueNumber=22&issueYear=2004&articleNumber=6. (Verified 9/3/04).
Shaner, Greg. 2004. Northern Corn Leaf Blight on Corn. Purdue Pest & Crop Newsletter (Aug 20). Purdue Univ. Extension. Available online at www.entm.purdue.edu/entomology/ext/targets/p&c/P&C2004/P&C23_2004.pdf. (URL verified 9/3/04).
Shaner, G. and D. Scott. 1998. Stalk Rots of Corn. Purdue Univ. Extension Publication BP-59. Available online at www.ces.purdue.edu/extmedia/BP/BP-59.pm65.pdf. (URL verified 9/3/04).
Shaner, G., P. Sellers, and D. Scott. 1998. Gray Leaf Spot. Purdue Univ. Extension Publication BP-56. Available online at www.ces.purdue.edu/extmedia/BP/BP-56.pdf. (URL verified 9/3/04).
Vincelli, Paul. 2004. Factors That Could Enhance Stalk Rots in Corn. Kentucky Pest News (Aug 2). Univ. of Kentucky. Available online at www.uky.edu/Agriculture/kpn/kpn_04/pn040802.htm#corrot. (URL verified 9/3/04).
Reports of arrested ear development in corn seem to return every year like the swallows of Capistrano. Arrested ear development goes by several other names: blunt ear syndrome (BES), beer can ears, and hand grenade ears to name a few. When growers discover the problem in their fields, they sometimes use other names that I cannot repeat in this article.
I won't go into details about the symptoms of BES, other than kernel row number is usually normal for the hybrid, but kernels per row and overall cob length are abruptly truncated. The abrupt arrest of ear development suggests a single stress event as the causal agent. I wrote a more extensive treatise on the subject last year (Nielsen, 2003) that included some references on possible causes of the problem.
In the past week, I discovered classical BES symptoms in a commercial hybrid and an apparent severe expression of the oddity in a seed production field, both in southern Michigan. I have also received reports of arrested ears in commercial hybrids from Ohio and Pennsylvania. If you come across this oddity yourself, please contact me with any details you can provide about the affected field (see below).
Desired Information About BES-Affected Fields:
Nielsen, R.L. (Bob). 2003. Blunt Ear Syndrome in Corn. Corny News Network, Purdue Univ. Available online at www.kingcorn.org/news/articles.03/BeerCanEars-0812.html. (URL verified 9/6/04).
For other Corny News Network articles, browse through the CNN Archives at www.kingcorn.org/news/index-cnn.html.
For other information about corn, take a look at the Corn Growers’ Guidebook at www.kingcorn.org.