Dandelion
(Taraxacum officinale Weber.)
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Table of Contents
- History
- Life Cycle
- Distinguishing Characteristics
- Control in Corn
- Control in Soybeans
- Control in Winter Wheat
History
One of the most widespread and abundant weeds in Ontario growing
in virtually every type of habitat.
Life Cycle
Perennial, reproducing only by seed.
Distinguishing Characteristics
Probably the most easily identified weed, dandelion contains a milky
white juice, a deep taproot, irregularly lobed leaves and a yellow
flower head. For more information refer to Page 252 in OMAF Publication
505 - Ontario Weeds.
Dandelion
Pictures
Each thumbnail image links to a larger image
Herbicide Control in Field Corn
Pre-Plant Control:
Pre-plant applications are effective at controlling established dandelions
and newly emerged seedlings. A number of herbicides and tank-mixes
will provide adequate control (Table 1). Certain
products and tank-mixes stipulate cropping restrictions (Table
2).
Table 1. Visual control of dandelion
in the spring, following pre-plant (PP) applications of various herbicides
| Active Ingredient |
Trade Name (product rate/acre) |
% Control
|
| glyphosate |
glyphosate (2 L/ac) |
94
|
| glyphosate + 2,4-D Ester |
glyphosate (1 L/ac) + 2,4-D Ester (0.5 L/ac) |
93
|
| glyphosate |
glyphosate (1.5 L/ac) |
91
|
| 2,4-D Ester |
2,4-D Ester (1 L/ac) |
89
|
| glyphosate + amitrol |
glyphoate (1 L/ac) + AMITROLE 240 (1 L/ac) |
88
|
| glyphosate + dicamba |
glyphosate (1 L/ac) + BANVEL II (0.25 L/ac) |
85
|
| dicamba |
BANVEL II (0.5 L/ac) |
51
|
Table 2. A summary of cropping restrictions
that exist with fall or spring applications*
| Trade Name |
Restrictions |
| AMITROL 240 |
If planting corn and whitebeans wait 10-14 days
after application before planting. If planting soybeans wait 6
days after applications before planting. |
| BANVEL II |
If applied alone or with glyphosate before September
1st, then field corn, soybean, spring cereals and canola can be
planted in the spring. If applied after September 1st or in the
spring, then only field corn can be planted after application. |
| 2,4-D Ester |
Use only the low rate (0.5 L/ac) in the spring.
Only field corn or spring cereals can be planted after a spring
application, however a 14 day interval between application and
planting is required. No specific crop restrictions are mentioned
when applied alone or with glyphosate in the fall. However, to
be safe, 2,4-D should be treated the same as BANVEL II. |
* A guideline only. The user must consult the manufacturer's product
label before using any of the products mentioned in the section.
Pre or Post Emergent Control
A pre-plant or fall applied application is ideal for dandelion control
in corn. If either one of those applications couldn't be made then
based on limited research, a post-emergent application of Banvel II
should provide good control of dandelion (Table
3).
Field experience has suggested that pre-emerge applications of isoxaflutole/atrazine
(CONVERGE) or post-emergent applications of nicosulfuron/rimsulfuron
+ diflufenzopyr/dicamba (ULTIM TOTAL) can be effective at controlling
dandelion.
Table 3. Control of dandelion in field
corn using various post-emergent herbicides
| Active Ingredient |
Trade Name (application timing) |
% Control
|
| dicamba |
BANVEL II (post - high rate) |
89
|
| dicamba/atrazine |
MARKSMAN (post) |
74
|
| diflufenzopyr/dicamba |
DISTINCT (post) |
70
|
| 2,4-D/atrazine |
SHOTGUN (post) |
40
|
| atrazine |
numerous products exists (post) |
25
|
| bromoxynil + atrazine |
PARDNER or KORIL + atrazine (post) |
23
|
| primisulfuron/dicamba |
SUMMIT (post) |
20
|
| mesotrione |
CALLISTO (post) |
13
|
| prosulfuron/dicamba |
PEAKPLUS (post) |
10
|
Post Harvest Control
Fall herbicide applications are ideal for controlling larger established
dandelions. Cooler temperatures will trigger dandelion to move sugars
down to the taproot for storage. Applying a systemic herbicide in
the fall promotes movement of the active ingredient down to the roots
providing effective long-term control. In general numerous products
and tank-mixes provide adequate control of dandelion when applied
in the fall (Table 4). Deciding on which one
to use will depend on the weed spectrum, cost and rotational flexibility
of the specific herbicide or tank-mix. Refer to Table
2 and the product label for information on rotational restrictions.
Table 4. Visual control of dandelion
in the spring, following fall applications of various herbicides
| Active Ingredient |
Trade Name (rate/acre) |
% Control
|
| amitrole |
AMITROL 240 (3L/ac) |
96
|
| glyphosate + dicamba |
glyphosate (1 L/ac) + BANVEL II (0.25 L/ac) |
92
|
| glyphosate |
glyphosate (1.5 L/ac) |
91
|
| dicamba |
BANVEL II (0.5 L/ac) |
89
|
| 2,4-D |
2,4-D Ester (1 L/ac) |
89
|
| glyphosate + 2,4-D |
glyphosate (1 L/ac) + 2,4-D Ester (0.5 L/ac) |
89
|
| amitrole |
AMITROL 240 (2 L/ac) |
88
|
| glyphosate + amitrole |
glyphosate (1 L/ac) + AMITROL 240 (1
L/ac) |
86
|
Source:
Dr. Peter Sikkema, Ridgetown College, University of Guelph.
Number of Trials:
Tables 1 and 4 are based on a summary of 2 field trials.
Table 3 based on a summary of 1 field trial.
Herbicide Rates:
Rates used in this trial are listed in OMAF Publication 75 - Guide
to Weed Control.
Weed Stage:
Dandelion size ranged from 5 to 40 cm om diameter at the time of application.
What has been your experience?
We want your feedback. Let us know what you have experienced with
these or other products, as well as any other effective management
strategies.
Herbicide Control in Soybeans
Pre-Plant Control:
Pre-plant applications are effective at controlling established dandelions
and newly emerged seedlings. A number of herbicides and tank-mixes
will provide adequate control (Table 1). Certain
products and tank-mixes stipulate cropping restrictions (Table
2). BANVEL II or 2,4-D products CANNOT be applied in the
spring prior to planting soybean as unacceptable crop injury can occur.
Table 1. Visual control of dandelion
in the spring, following pre-plant (PP) applications of various herbicides
| Active Ingredient |
Trade Name (product rate/acre) |
% Control
|
| glyphosate |
glyphosate (2 L/ac) |
94
|
| glyphosate + 2,4-D Ester |
glyphosate (1 L/ac) + 2,4-D Ester (0.5 L/ac) |
93
|
| glyphosate |
glyphosate (1.5 L/ac) |
91
|
| 2,4-D Ester |
2,4-D Ester (1 L/ac) |
89
|
| glyphosate + amitrol |
glyphoate (1 L/ac) + AMITROLE 240 (1 L/ac) |
88
|
| glyphosate + dicamba |
glyphosate (1 L/ac) + BANVEL II (0.25 L/ac) |
85
|
| dicamba |
BANVEL II (0.5 L/ac) |
51
|
Table 2. A summary of cropping restrictions
that exist with fall or spring applications*
| Trade Name |
Restrictions |
| AMITROL 240 |
If planting corn and whitebeans wait 10-14 days
after application before planting. If planting soybeans wait 6
days after applications before planting. |
| BANVEL II |
If applied alone or with glyphosate before September
1st, then field corn, soybean, spring cereals and canola can be
planted in the spring. If applied after September 1st or in the
spring, then only field corn can be planted after application. |
| 2,4-D Ester |
Use only the low rate (0.5 L/ac) in the spring.
Only field corn or spring cereals can be planted after a spring
application, however a 14 day interval between application and
planting is required. No specific crop restrictions are mentioned
when applied alone or with glyphosate in the fall. However, to
be safe, 2,4-D should be treated the same as BANVEL II. |
* A guideline only. The user must consult the manufacturer's product
label before using any of the products mentioned in the section.
Post Emergent Control
Field observations have shown that chlorimuron-ethyl (CLASSIC) will
provide good post-emergent and residual control of dandelion seedlings
provided they are less than 15 cm. in diameter.
Post Harvest Control
Fall herbicide applications are ideal for controlling larger established
dandelions. Cooler temperatures will trigger dandelion to move sugars
down to the taproot for storage. Applying a systemic herbicide in
the fall promotes movement of the active ingredient down to the roots
providing effective long-term control. In general numerous products
and tank-mixes provide adequate control of dandelion when applied
in the fall (Table 4). Deciding on which one
to use will depend on the weed spectrum, cost and rotational flexibility
of the specific herbicide or tank-mix. Refer to Table
2 and the product label for information on rotational restrictions.
Table 4. Visual control of dandelion
in the spring, following fall applications of various herbicides
| Active Ingredient |
Trade Name (rate/acre) |
% Control
|
| amitrole |
AMITROL 240 (3L/ac) |
96
|
| glyphosate + dicamba |
glyphosate (1 L/ac) + BANVEL II (0.25 L/ac) |
92
|
| glyphosate |
glyphosate (1.5 L/ac) |
91
|
| dicamba |
BANVEL II (0.5 L/ac) |
89
|
| 2,4-D |
2,4-D Ester (1 L/ac) |
89
|
| glyphosate + 2,4-D |
glyphosate (1 L/ac) + 2,4-D Ester (0.5 L/ac) |
89
|
| amitrole |
AMITROL 240 (2 L/ac) |
88
|
| glyphosate + amitrole |
glyphosate (1 L/ac) + AMITROL 240 (1 L/ac) |
86
|
Source:
Dr. Peter Sikkema, Ridgetown College, University of Guelph.
Number of Trials:
Tables 1 and 3are based on a summary of 2 field trials.
Herbicide Rates:
Rates used in this trial are listed in OMAF Publication 75 - Guide
to Weed Control.
Weed Stage:
Dandelion size ranged from 5 to 40 cm om diameter at the time of application.
What has been your experience?
We want your feedback. Let us know what you have experienced with
these or other products, as well as any other effective management
strategies.
Herbicide Control in Winter Wheat
Post Emergent Control
Estaprop, Turboprop or Dichlorprop-D are the only products that provide
adequate control of dandelion. Winter wheat fields should be scouted
for the presence of dandelions in mid to late April and if present
in high enough populations should be treated as early as possible.
Late applications of Estaprop, turboprop or Dichlorprop-D can cause
unacceptable levels of crop injury and therefore should be applied
before the late tillering or 1st node stage of winter wheat.
Table 1. Visual control of dandelion in winter wheat using
various post-emergent herbicides
| Active Ingredient |
Trade Name |
% Control
|
| dichlorprop/2,4-D |
ESTAPROP, TURBOPROP, or DICHLORPROP D |
91
|
| bromoxynil/MCPA |
BUCTRIL M, BADGE or MEXTROL |
64
|
| 2,4-D |
2,4-D Amine (Numerous Brands Exist) |
61
|
| MCPA |
MCPA AMINE (Numerous Brands Exist) |
61
|
| dicamba/MCPA/mecoprop |
SWORD or TARGET |
61
|
| thifensulfuron-methyl/tribenuron methyl |
REFINE EXTRA |
56
|
Source:
Dr. Peter Sikkema, Ridgetown College, University of Guelph.
Number of Trials:
Tables 1 is based on a summary of 3 field trials.
Herbicide Rates:
Rates used in this trial are listed in OMAF Publication 75 - Guide
to Weed Control.
Weed Stage:
Dandelion size ranged from 5 to 40 cm om diameter at the time of application.
What has been your experience?
We want your feedback. Let us know what you have experienced with
these or other products, as well as any other effective management
strategies.
