U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 Application Technology Research: Wooster, OH
 close



    Research

                    Research Projects
                                    Publications
                                    Collaborations
                                    News
                                    Software
                People

                    Staff Listing
                                    Careers


        


                    Departments
                        Agricultural Engineering
                                    Entomology
                                    Horticulture
                                    Plant Pathology
                                    IR-4 programSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Midwest Area Wooster, Ohio Application Technology Research Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications

Title:   Author  item
                                            Altland, Jamesitem
                                            GLENN, WEHTJE - AUBURN UNIVERSITYitem
                                            GILLIAM, CHARLES - AUBURN UNIVERSITY
  Submitted to: Weed Technology
                                    Publication Type: Peer Reviewed Journal
                                    Publication Acceptance Date: 5/12/2008
                                    Publication  Date: 7/28/2008
                                    Citation: Altland, J.E., Glenn, W., Gilliam, C. 2008. Interaction of Glyphosate and Diquat in Ready-To-Use Weed Control Products. Weed Technology. 22(3):472-476.Interpretive Summary: Glyphosate is the most commonly used herbicide for postemergence weed control in home landscapes.  Glyphosate is commonly pre-mixed with other herbicides, such as diquat, to provide 'faster control'.  The objective of this research was to determine if additional herbicides added to glyphosate offer a synergistic or antagonistic effect on weed control.  Results show that while weeds appeared to die more quickly with diquat added to the spray solution, the same weeds regrew at a faster rate.  Adding diquat to the glyphosate spray caused weed foliage to rapidly dessicate, preventing movement of the glyphosate herbicide throughout the rest of the plant (parts not contacted by the spray, such as the roots).  This research lends clarity to the decision of adding additional herbicides to glyphosate for weed control.  When rapid weed burndown is desirable, adding diquat to glyphosate is justified; however, when long-term weed control is desired glyphosate should be applied alone.  Better decisions on herbicide selection will ultimately lead consumers to use less herbicide more effectively.
                                Technical Abstract: Glyphosate-based, ready-to-use weed control products frequently contain diquat (typically 0.04 by weight relative to glyphosate) under the supposition that the diquat, “makes glyphosate work faster“.  However, in light of the known modes of actions of glyphosate and diquat, we hypothesize that diquat may be antagonistic to glyphosate activity.  Greenhouse experiments using longstalked phyllanthus were conducted to test this hypothesis.  Glyphosate was applied at a series of rates, ranging from 0.11 to 1.12 kg ae/ha, either alone or tank mixed with either 0, 0.02, 0.04 and 0.06 diquat.  Onset of visual injury was more pronounced with the glyphosate +diquat tank mixtures compared to glyphosate alone.  However long term control, as expressed by regrowth suppression, was greater with glyphosate alone.  Regression analysis indicated that at marginally effective glyphosate rates, the amount of glyphosate must be increased by approximately 60% to compensate for the diquat-based antagonism.  Absorption and translocation studies using 14C glyphosate revealed that the antagonism of diquat toward glyphosate can be attributed to reduced translocation of absorbed glyphosate.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov