CORN Newsletter: 2009-10, April 21, 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 2009-10
April 21, 2009 - April 28, 2009

Back to main issue

Low Temperatures and Corn Emergence
by Peter Thomison


	Print this story Email this story Handheld devices

What impact will recent weather conditions have on corn that’s already been planted? Some fields were planted several weeks ago before soils were saturated by persistent rains. In past years, we have observed that early planted corn that was in the process of germinating or as far along as the V1 stage (one leaf collar visible) survived freezing temperatures in late April with little impact on crop performance or plant stand. Agronomists generally downplay the impact of low temperature injury in corn because the growing point is at or below the soil surface until V6 (six leaf collars visible), and thereby relatively safe from freezing air temperatures. However when dry corn seed absorbs cold water as a result of a cold rain or melting snow, “imbibitional chilling injury” may result. Cold water can cause similar injury to seedling structures as they emerge during germination. Such physiological injury was widely observed in 2005 when early planted corn in various stages of germination and emergence was subjected to a period freezing rain and snow followed by temperatures at or below 50 degree F for about 10 days. What we’ve experienced thus far in 2007 is mild in comparison to 2005.

To assess the impact of these freezing temperatures on emerged corn, check plants about 5 days after the freezing injury occurred (and preferably when growing conditions conducive for regrowth have occurred). New leaf tissue should be emerging from the whorl. You can also observe the condition of the growing point (usually located ½ in to 3/4 in below the soil surface) by splitting seedlings lengthwise. If the growing point appears white to light yellow and firm several days after the frost, prognosis for recovery is good.

Of greater concern with regard to the viability of germinating and emerging corn is how long soils will remain saturated. Cool temperatures and wet weather provide the right conditions for the development of seedling blight diseases. Cold temperature injury can play a significant role in predisposing plants to root infection and blight. Under normal conditions plants can continue to grow and produce new roots, but when other injuries occur, new roots cannot develop rapidly and Pythium and other soil fungi can kill stressed plants. Seed treatment fungicides generally remain effective from 10 to 14 days but under saturated conditions the duration of protection may be shorter.

For more detailed information on corn germination and emergence, check out the series of excellent articles (noted below) which Dr. Bob Nielsen, my counterpart at Purdue University has written. These articles include great photos that will assist your understanding of these growth and development processes.
Nielsen, R.L. 2008. Germination Events in Corn. Corny News Network, Purdue Univ. [On-Line]. Available at http://www.kingcorn.org/news/timeless/GerminationEvents.html.

Nielsen, R.L. 2008. The Emergence Process in Corn. Corny News Network, Purdue Univ. [On-Line]. Available at http://www.kingcorn.org/news/timeless/Emergence.html.

Nielsen, R.L. 2008. Heat Unit Concepts Related to Corn Development. Corny News Network, Purdue Univ. [On-Line]. Available at http://www.kingcorn.org/news/timeless/HeatUnits.html.

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