Crops Bulletin
June 5, 2014 
Issue 4    

Prepared by

Paul Kassel

Extension Field Agronomist



(712) 262-2264




Serving Clay, Buena Vista, Dickinson, Emmet, Hancock, Kossuth, Palo Alto, Pocahontas, Sac and Winnebago Counties



The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, gender, religion, age, disability, political beliefs, sexual orientation, and marital or family status. (Not all prohibited bases apply to all programs.) Many materials can be made available in alternative formats for ADA clients. To file a complaint of discrimination, write USDA, Office of Civil Rights, Room 326-W, Whitten Building, 14th and Independence Avenue, SW, Washington, DC 20250-9410 or call 202-720-5964.


Fomesafen Carryover: Fomesafen is the active ingredient in Flexstar, Reflex (and one of the ingredients in Prefix). There is a 10 month crop rotation restriction to corn with fomesafen. The 10 month rotation of fomesafen can be termed an agronomic restriction, because Fomesafen can carryover and injure corn.  More information is available from this article by Bob Hartzler.  


Dry soil conditions in last season may have delayed the breakdown of fomesafen. Fomesafen degrades better with moist soil conditions after application.


Product                    rate/acre          lb of fomesafen active ing./acre

Flexstar                  16 fl oz                      0.235

Reflex                     16 fl oz                      0.25

Flexstar GT 3.5        3.0 pt                        0.21

Marvel                     7.3 fl oz                     0.16

Prefix                      2.0 pt                        0.25


Nitrogen Tests:   The late spring nitrogen test (LSNT) can be useful to confirm nitrogen (N) levels or nitrogen needs. Fields that have had manure with questionable N content, or fields where N rates were less than planned may be good candidates for the LSNT.


Weed Control in Larger Corn: The following is some selected information for weed control in larger sized corn.


Product           Corn Size/Stage    Notes on Weed Control


Atrazine              up to 12 inch

Callisto               V8, or 30 inch        up to 10-inch 

                                                      lambsquarter, waterhemp 

Capreno              6                           up to 6 inch

                                                      lambsquarter, waterhemp 

Glyphosate          V8 or 30 inch ht     rates are weed size  


Halex GT             V8

Impact/Armezon   V8                        6 inch lambsquarter,  


Laudis                 up to V9                6 inch lambsquarter,  

  waterhemp, velvetleaf  

Liberty                 up to V7                4-6 inch weeds

Realm Q              V6 or 20 inch        1-2 inch grass, 5 inch  


Status                 V10, or 36 inch      3-4 inch weeds  

Surestart             11 inch corn

Prepared by Paul Kassel, Extension Field Agronomist

Phone: (712) 262-2264, Email: