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Horseweed |
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Horseweed (Conyza canadensis) is the most widespread resistant weed of Delaware
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| Introduction |
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About this page |
| There are currently 7 different types (known as 'biotypes') of herbicide resistant weeds in Delaware. The first herbicide resistant weed reported from Delaware is Smooth Pigweed (Amaranthus hybridus) with resistance to atrazine, reported in 1977. Local weed scientists estimate that there are 640 sites and more than 60,900 acres infested with herbicide resistant weeds in Delaware and they infest corn, soybean, and vegetables. The most widespread resistant weed of Delaware is Horseweed (Conyza canadensis), which infests an estimated 10001-100000 acres and is found primarily in soybean. Common Ragweed (Ambrosia artemisiifolia), with resistance to acifluorfen-Na, carfentrazone-ethyl, chlorimuron-ethyl, cloransulam-methyl, flumiclorac-pentyl, flumioxazin, fomesafen, halosulfuron-methyl, imazamox, imazapyr, imazaquin, imazethapyr, iodosulfuron-methyl-sodium, lactofen, metsulfuron-methyl, oxyfluorfen, primisulfuron-methyl, pyraflufen-ethyl, pyrithiobac-Na, sulfentrazone, and trifloxysulfuron-sodium is the most recently discovered (2005) new type of resistant weed in Delaware. |
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This is a resource page to assist you in
managing herbicide-resistant weeds in Delaware . If you have any questions regarding herbicide-resistant
weeds in Delaware please contact an
expert in your area. If you have encountered a computer related error on the site then contact
support@weedscience.org. If you are a weed scientist wanting to add or correct information on this page then please contact
research@weedscience.org
or add the
information directly.
Scroll down this page to view tables on
herbicide resistant weeds in Delaware and its adjacent states as well as a list of articles about
herbicide resistant weeds in your region. Click on the links within
the table to view a case of resistance in more detail.
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HERBICIDE RESISTANT WEEDS IN DELAWARE | | Weed | Situation | Herbicide Mode of Action | Year | Smooth Pigweed
(Amaranthus hybridus) | corn | C1/5 - Photosystem II inhibitors
(atrazine) | 1977 | Lambsquarters
(Chenopodium album) | corn | C1/5 - Photosystem II inhibitors
(atrazine) | 1988 | Smooth Pigweed
(Amaranthus hybridus) | vegetables | B/2 - ALS inhibitors
(imazethapyr) | 2000 | Horseweed
(Conyza canadensis) | soybean | G/9 - Glycines
(glyphosate) | 2000 | Horseweed
(Conyza canadensis) | soybean | D/22 - Bipyridiliums
(paraquat) | 2003 | Common Ragweed
(Ambrosia artemisiifolia) | soybean | B/2 - ALS inhibitors
(acifluorfen-Na, carfentrazone-ethyl, chlorimuron-ethyl, cloransulam-methyl, flumiclorac-pentyl, flumioxazin, fomesafen, halosulfuron-methyl, imazamox, imazapyr, imazaquin, imazethapyr, iodosulfuron-methyl-sodium, lactofen, metsulfuron-methyl, oxyfluorfen, primisulfuron-methyl, pyraflufen-ethyl, pyrithiobac-Na, sulfentrazone, trifloxysulfuron-sodium) | 2005 | Common Ragweed
(Ambrosia artemisiifolia) | soybean | E/14 - PPO inhibitors
(acifluorfen-Na, carfentrazone-ethyl, chlorimuron-ethyl, cloransulam-methyl, flumiclorac-pentyl, flumioxazin, fomesafen, halosulfuron-methyl, imazamox, imazapyr, imazaquin, imazethapyr, iodosulfuron-methyl-sodium, lactofen, metsulfuron-methyl, oxyfluorfen, primisulfuron-methyl, pyraflufen-ethyl, pyrithiobac-Na, sulfentrazone, trifloxysulfuron-sodium) | 2005 |
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HERBICIDE RESISTANT WEEDS IN ADJACENT STATES | | | | | |
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HERBICIDE RESISTANT WEED CONTACTS IN DELAWARE
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Your local state
university extension agent or local department of agriculture
representative may be able to provide you with more information on
herbicide-resistant weeds in your region. Much of the information
about herbicide-resistant weeds in Delaware has been
provided by the following experts.
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STATE CONTACTS | | JOSEPHINE COTTERMAN | E. I. DuPont deNemours & Co.
Stine Haskell Research Center
P.O. Box 30 Elkton Road
Newark, 19714, Delaware
United States of America
Phone : (302) 366-6166
Fax : (302) 451-4863
Email Josephine Cotterman |
| | JERRY GREEN | Biologist
Pioneer Hi-Bred
P. O. Box 30
Stine-Haskell Research Center Bldg. 210
Newark, 19714-0030, Delaware
United States of America
Phone : (302) 366-5548
Fax : (302) 366-6120
Email Jerry Green |
| | LEONARD SAARI | Manager, Technology Transfer & Licensing
E.I. DuPont deNemours Company
Central Research and Development
P.O. Box 80328
Wilmington, 19880-0328, Delaware
United States of America
Phone : (302) 695-9360
Fax : (302) 695-1044
Email Leonard Saari |
| | MARK VANGESSEL | Univ. of Delaware
Res. and Educ. Center
Rd. 6, Box 48
Georgetown, 19947, Delaware
United States of America
Phone : (302) 856-7303
Fax : (302) 856-1845
Email Mark VanGessel |
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| Acknowledgements |
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Where to now? |
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The
North American Herbicide Resistance Action Committee and weed
scientists in Delaware have been instrumental in providing you this information.
Particular thanks is given to Josephine Cotterman, Jerry Green, Leonard Saari, and Mark VanGessel for providing detailed information.
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