CORN Newsletter: 2009-05, March 3, 2009

Crop Recommendation and Observation Network by the Agronomic Crops Team


	Home Newsletter Calendar Education Research Resources Decision Tools Photo Library About Us

Advanced Search

Corn
Soybean
Wheat
Forages
Weeds
Diseases
Insects
Crop Injury
Fertility
Equipment / Tillage
Precision Agric.
Soil & Water Mgt.
Environment
Identity Preserved
Weather
Ag Markets

E-mail Lists
Help
Contact Us
Advertise Us

C.O.R.N Newsletter 2009-05
March 3, 2009 - March 17, 2009

Back to main issue

Arrested ears and other ear oddities revisited
by Peter Thomison


	Print this story Email this story Handheld devices

In 2007, and to a lesser extent 2006, there were localized reports of “arrested ear” development in several Corn Belt states, especially Illinois and Indiana. Arrested ears were characterized by a range of symptoms. Some ears exhibited varying degrees of stunting with limited kernel formation. Some ear shoots carried either no ear or only the short remnant of an ear. Often silks were absent or limited.
Arrested ears usually occurred in fields that had been treated with various fungicides, herbicides, insecticides, foliar nitrogen, and various spray additives. However, some of the most pronounced arrested ear damage was associated with foliar fungicide applications made with ground equipment during the two week period prior to tasseling. In the various postmortem assessments, it was noted that arrested ear injury frequently occurred in fields where the foliar treatments included non-ionic surfactants. Now there is preliminary evidence from evaluations conducted in 2008 that suggests that the cause of some of these arrested ear problems may actually be due more to surfactants than fungicides.

Dr. Bob Nielsen at Purdue University evaluated the effects of a number of pesticides and spray additives on ear development in 2008. Three fungicides, one insecticide, a commercial non-ionic surfactant, crop oil concentrate, glyphosate, ammonium sulfate, and 2,4-D were applied in various combinations over the canopy of corn at approximately the V14 stage of leaf development (approximately 5 ft tall and 1 - 2 weeks prior to tasseling). Dr. Nielsen’s demonstrations revealed that neither fungicides alone or in combination with just an insecticide resulted in any severely arrested ears. The addition of crop oil concentrate or non-ionic surfactant to fungicides alone or fungicide + insecticide resulted in a frequency of severely arrested ears ranging from 3 to 35%. Further addition of glyphosate with a fungicide/insecticide/non-ionic surfactant combination resulted in 60% or greater arrested ears. Reductions in cob length ranged from 6 to 48% with the application of the various foliar pesticide and additive combinations.

Dr. Emerson Nafziger at the University of Illinois performed tests that compared an untreated check with a nonionic surfactant applied at the labeled rate of 0.25% and at 0.5% (2X), Headline fungicide at 6 oz per acre applied by itself and with each of the two non-ionic surfactant rates, and CoRoN foliar N by itself, at 4 gallons per acre. The foliar treatments were applied at V13-14. According to Dr. Nafziger, in plots with damage, symptoms ranged from slight ear size reduction and oddly angled ear shanks to complete loss of ears. Most common damage symptoms included "bouquet" ears formed by small ears trying to develop from the same shank as the main ear. The results showed that most of the damage came from the non-ionic surfactant by itself, and that increasing the concentration increased the amount of damage. Headline fungicide by itself did no injury compared to the untreated check, but adding fungicide to the non-ionic surfactant increased the damage by about 10 percentage points. About 10% of the plants in the 0.5% non-ionic surfactant treatment had no ears at all, regardless of whether Headline was used.

In trials conducted at the OSU Western Agriculture Research Station near S. Charleston we evaluated Headline fungicide applications at various vegetative stages including V12-14. Non-ionic surfactants were not included in these treatments. No ear abnormalities or injury was observed.

Results of the Purdue and Illinois work indicate non-ionic surfactants applied at approximately V13-V14 can adversely affect ear development in corn. For more details and some excellent pictures documenting the injury potential from such pretassel applications check the following:

Nafziger, E. 2008. More ear oddities, and a possible cause. The Bulletin, Univ. of Illinois. [on-line]. Available at http://www.ipm.uiuc.edu/bulletin/article.php?id=1033
(URL accessed 3/2/09).

Nielsen, R.L., W. Wise, C. Gerber. 2008. Arrested ears resulting from pre-tassel applications of pesticide & spray additive combinations. Corny News Network, Purdue Univ. [on-line]. Available at http://www.kingcorn.org/news/articles.08/ArrestedEars-1209.html (URL accessed 3/2/09).

Readers can subscribe electronically to this newsletter by signing up at http://agcrops.osu.edu/services/email.html. E-mail labarge.1@osu.edu if you have problems subscribing or no longer wish to receive this newsletter.

C.O.R.N. is a summary of crop observations, related information, and appropriate recommendations for Ohio Crop Producers and Industry. C.O.R.N. is produced by the Ohio State University Extension Agronomy Team, State Specialists at The Ohio State University and Ohio Agricultural Research and Development Center. C.O.R.N. Questions are directed to State Specialists, Extension Associates, and Agents associated with Ohio State University Extension and the Ohio Agricultural Research and Development Center at The Ohio State University.

Information presented above and where trade names are used, they are supplied with the understanding that no discrimination is intended and no endorsement 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.

All educational programs conducted by Ohio State University Extension are available to clientele on a nondiscriminatory basis without regard to race, color, creed, religion, sexual orientation, national origin, gender, age, disability or Vietnam-era veteran status.

Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, Keith L. Smith, Director, Ohio State University Extension.

TDD # 1 (800) 589-8292 (Ohio only) or (614) 292-1868


Home \| Newsletter \| Calendar \| Education \| Research \| Resources \| Decision Tools \| Photo Library \| About	[top]


Copyright by The Ohio State University 2003 Agriculture and Natural Resources, OSU Extension, ATI, OARDC, College of Food, Agriculture, and Environmental Sciences