C.O.R.N. Newsletter 2010-35

Dates Covered: 
October 19, 2010 - October 25, 2010
Editor: 
Curtis Young

New Weed Identification Resources

There is finally a weed identification book with photos that addresses weeds in our area, Weeds of the Midwestern United States and Central Canada.   This weed ID book features more than 1,400 full-color photographs and 363 maps, and provides essential information on more than 350 of the most troublesome weedy and invasive plants found in this region.  The guide identifies each plant at various stages of its life cycle, and offers useful details about its origin, habitat, morphology, biology, distribution, and toxic properties.  The book also includes illustrations of the most common characteristics of plants and terms used to describe them, a key to plant families included in the book, a glossary of frequently used terms, a bibliography, and indexes of scientific and common plant names.

Each species account includes:

  • Distribution map and up to four color photographs showing seed, seedling, plant & flower
  • Scientific names, common names, and local synonyms of common names
  • Vegetative characteristics for seedlings and leaves
  • Notes on special identifying characteristics, reproductive characteristics, and toxic properties

We highly recommend the addition of this to your weed ID library.  So far, we have found ordering through Amazon.com to be the cheapest way to buy the book, but you should be able to order it through your local bookstore.  Current price on Amazon - $29.67.

Michigan State University has developed a smaller weed ID publication, "An IPM Pocket Guide for Weed Identification in Field Crops," which can be handy to carry around.  This publication is available from the MSU Bulletin Office as Bulletin E-3081, for $16.00.  Link to the MSU newsletter article on this: http://www.ipmnews.msu.edu/fieldcrop/fieldcrop/tabid/56/articleType/ArticleView/articleId/2314/New-weed-identification-guide-available.aspx

Brown Marmorated Stink BugBrown Marmorated Stink Bug

Brown Marmorated Stink Bug

Last July, we discussed the possibility of a new insect that is moving eastward from the Atlantic Coast into the eastern Corn Belt becoming a pest in Ohio on soybeans and other crops, the brown marmorated stink bug.   This insect, currently causing great concern in eastern U.S., has the potential to be a problem to field, vegetable, and fruit crops, and on ornamentals.   To add insult to injury, these stink bugs then tend to move into people's homes in late fall looking for overwintering sites in numbers reaching the hundreds and even thousands.  And as the name implies, the insect can release a characteristic pungent acid odor that many people find offensive; in other words, these insects can "stink!"  This insect has been written about in numerous newspapers and magazines including Time!

This past week, we received a number of reports of homes in Ohio being invaded by this insect.   Although not in the 1,000s or even 100s, they nevertheless were easily found.  In discussing this with colleagues from the east, some mentioned that high, damaging populations often occur about two years after they are first discovered in an area.   Thus, we feel it is imperative to determine where in the state this stink bug is currently being found; the easiest way to accomplish this is to hear from home owners that are finding them in their homes.  If you find any of these stink bug, please contact your nearest County Extension educator or contact us at hammond.5@osu.edu

We would like you to either send the insects sent to us, or at least a good picture, preferable with a digital camera and not a cell phone, which can be used for proper identification. 

Further information on the brown marmorated stink bug is available in a fact sheet written by Celeste Welty and others available at http://entomology.osu.edu/ag/images/Marmorated_Stink_Bug.pdf.  On the adult stink bug, note the alternating dark and light bands on the last two segments of the antennae, and the alternating light and dark banding on the exposed sides of the abdomen as shown in the picture.  Thank you for your assistance.

Hybrid Selection Tips

Although results of the 2010 Ohio Corn Performance Trials (and those of neighboring states) have yet to be published, many growers are already making decisions about hybrids to plant in 2011.  Hybrid selection is one of the most important management decisions a corn grower makes each year.  It's a decision that warrants careful a comparison of performance data.  It should not be made in haste or based on limited data. 

Planting a marginal hybrid or one not suitable for a particular production environment imposes a ceiling on the yield potential of a field before it's been planted.  In past years of the Ohio Corn Performance Tests, hybrid entries of similar maturity have differed in yield by as much as 60 bu/A or more depending on test site.  Growers should choose hybrids best suited to their farm operation.  Corn acreage, previous crop, soil type, tillage practices, desired harvest moisture, and pest problems determine the relative importance of such traits as drydown, insect and disease resistance, early plant vigor, plant height, etc. 

End uses of corn should also be considered - is corn to be used for grain or silage?  Is it to be sold directly to the elevator as shelled grain or used on the farm?  Are there premiums available at nearby elevators or from end users for identity-preserved (IP) specialty corns such as food grade or non-GMO corn?  Capacity to harvest, dry and store grain also needs consideration.  The following are some tips to consider in choosing hybrids that are best suited to various production systems.

  1. Select hybrids with maturity ratings appropriate for your geographic area or circumstances. Corn for grain should reach physiological maturity or "black layer" (maximum kernel dry weight) one to two weeks before the first killing frost in the fall.  In some years (remember 2009), grain drying can be a major cost in corn production.  Use days-to-maturity, growing degree day (GDD) ratings, and harvest grain moisture data from performance trials to determine differences in hybrid maturity.  This year harvest grain moisture may be of somewhat limited value in assessing differences in hybrid maturity because extraordinarily warm, dry conditions in August and September resulted in rapid dry down.  As a result, the grain moisture of early and full season hybrids was often below 20% at harvest and differed little.
  2. Choose hybrids that have produced consistently high yields across a number of locations. Choosing a hybrid simply because it's a "triple stack" or "quad stack" or possesses appealing cosmetic traits, like "flex" ears, will not ensure high yields; instead, look for yield consistency across environments. Hybrids will perform differently, based on region, soils and environmental conditions, and growers should not rely solely on one hybrid characteristic or transgenic traits to make their product selection. The 2009 Ohio Corn Performance Tests revealed that several non-transgenic hybrids suitable for non-GMO grain production produced yields comparable to the highest yielding triple/quad stack entries. However,  when planting fields where corn rootworm (RW) and European corn borer (ECB) are likely to be problems (in the case of RW - continuous corn, presence of the rootworm variant, and in the case of ECB - very late plantings),  Bt traits offer outstanding protection and may mitigate the impact of other stress conditions.
  3. Plant hybrids with good standability to minimize stalk lodging.  This is particularly important in areas where stalk rots are perennial problems, or where field drying is anticipated.  If a grower has his own drying facilities and is prepared to harvest at relatively high moisture levels (>25%), then standability and fast drydown rates may be somewhat less critical as selection criteria.  There are some hybrids that have outstanding yield potential but are more prone to lodging problems under certain environmental conditions after they reach harvest maturity.
  4. Select hybrids with resistance and/or tolerance to stalk rots, foliar diseases, and ear rots. Consult the Ohio Field Crops Diseases web page online at http://www.oardc.ohio-state.edu/ohiofieldcropdisease/ for the most common disease problems of corn in Ohio.  In recent years, several diseases have adversely affected the corn crop - including northern corn leaf blight, Stewart's bacterial leaf blight, Gibberella and Diplodia ear rots.  Corn growers should obtain information from their seed dealer on hybrid reactions to specific diseases that have caused problems or that have occurred locally.
  5. Never purchase a hybrid without consulting performance data.  Results of state, company, and county replicated hybrid performance trials should be reviewed before purchasing hybrids.  Because weather conditions are unpredictable, the most reliable way to select superior hybrids is to consider performance during the last year and the previous year over as wide a range of locations and climatic conditions as possible.  However, multi-year data for hybrids is becoming increasing difficult to obtain. If limited to single year data, it's important to try to evaluate a hybrid's performance across a range of different growing conditions.  For example compare the hybrid's performance at test sites where rainfall was adequate with those where rainfall was limited and stress conditions may have occurred.  To assess a hybrid's yield averaged across multiple Ohio test sites consult the "Combined Regional Summary of Hybrid Performance" tables.  These tables and other results for the Ohio Corn Performance Trial will be available online: http://www.ag.ohio-state.edu/~perf/ in the near future.

For more pointers and thoughts on hybrid selection, check the following:

Lauer, Joe.  2010.  Pressured to Place that Corn Seed Order?  Remember the Basics.  Wisconsin Crop Manager Newsletter, Univ of Wisconsin Extension.  Available at: http://ipcm.wisc.edu/WCMNews/tabid/53/EntryId/1045/Pressured-to-Place-that-Corn-Seed-Order-Remember-the-Basics.aspx  (URL accessed Oct 18 2010).

Nielsen, R.L.  2010.  Hybrid Selection: Where's the Beef?  Corny News Network, Purdue Univ.  Available at: http://www.kingcorn.org/news/timeless/HybridSeln.html  (URL accessed Oct 18 2010)

Correction to Fall Application of Anhydrous Ammonia - A Good Idea?

A small yet very significant word was inadvertently omitted from last week's article on anhydrous applications.  In the third paragraph of the article, the last sentence of the paragraph read, "Realize that the inhibitor does provide inhibition indefinitely, so still try to make applications in cooler soil temperatures."  The word that was omitted was "NOT."  Thus the sentence should have read, "Realize that the inhibitor does NOT provide inhibition indefinitely, so still try to make applications in cooler soil temperatures."

 

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About the C.O.R.N. Newsletter

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.