Solutions for the Growing World
INVASIVE WATCH
Leafy Spurge (Euphorbia esula)
Leafy Spurge (Euphorbia esula)
Leafy Spurge is a deep rooted, non-native perennial plant
capable of vigorous vegetative growth. Dense infestations of the
weed often create biologically sterile monocultures excluding
desirable vegetation. The displacement of desirable vegetation
by leafy spurge significantly reduces the economic value of
infested rangeland. Leafy spurge is a cold season broadleaf
plant beginning growth early in the spring. The root system can
penetrate as deep as 29 feet which allows the plant to survive
extreme droughts, yet it can also tolerate months of flooding.
Much of the leafy spurge root system contains reproductive buds
capable of producing new shoots which can emerge from depths
of up to three feet. Each flower produces a capsule that contains
three seeds. When the stem matures, the capsules explode
propelling seeds up to 15 feet. A single flowering stem may
produce over 150 seeds. Leafy spurge infests many habitats such
as roadsides, other non-crop areas, riparian wetlands, wildlands,
rangelands and pastures.
Do not treat too early in the spring. Leafy spurge is the most
sensitive to herbicide treatments applied when the true flowers
(after yellow bract is formed) and plants are developing (spring
or early summer) or in early to mid-September after the stems
have developed new fall re-growth. Herbicide applications after
seed dispersal as the plants become dormant during the hot,
dry summer are not as effective. Refer to the application timing
graph on the lower left which shows growth stages for optimum
control.Herbicide applications in excess of 25-50 gallons of spray
solution per acre, depending on leafy spurge canopy, will allow the
herbicide to penetrate the leafy spurge vegetative canopy and may
increase control due to increased herbicide uptake by roots.
Rate Recommendations
Apply Tordon® 22K (picloram) alone at 1-2 quarts/acre. Add 2,4D at 1 quart/acre (1 lb ae/acre) to rates below 1 quart/acre of
Tordon 22K. Research has shown that the addition of OverDrive
at 4 oz product/acre may improve leafy spurge control by up to
20%. Reducing the Tordon rate below 1 quart/acre when mixing
with OverDrive is not recommended. Add a non-ionic surfactant or
Commitment
blend at 0.25% v/v (1 pint/100 gallons). Herbicide re-treatments
Control of leafy spurge requires a long term commitment and
re-treatment of seedlings and new plants from root buds. Treated should be made when control drops below 75% in successive
years.
sites must be evaluated and checked each year and new plants
re-treated with the objective of ether containing the perimeter
For control of noxious or invasive weeds as listed by federal states,
of mature infestations and utilizing other integrated tools within
or local authorities, do not apply more than 1.0 lb active ingredient
boundaries or controlling infestations less than 5 years old.
(2 quarts of Tordon 22K/acre) per annual growing season as a
broadcast treatment.
Sensitive Sites (around trees, near water, or other areas not suitable
for certain herbicides such as picloram or aminocyclopyraclor)
Apply ForeFront® HL at 2.1 pints/acre plus OverDrive at 4 oz/acre
or a tank mix of 7 fl oz/acre Milestone® plus 1 quart/acre 2,4-D
plus 4 oz/acre of OverDrive.
Graph reprinted by permission. Leafy spurge identification and control. R.G. Lym
and C.G. Messersmith. NDSU Ext. Ser. Bull 765
Research results have shown this mixture to provide excellent inseason control of leafy spurge with up to 75% stand reduction the
following year. Re-treatment will be necessary in successive years
for long term control.
INVASIVE WATCH: Leafy Spurge
Spot or Patch Treatment with Backpack or Small Volume Sprayers
For treatment with small sprayers, use the following charts (table
1 for liquids and Table 2 for OverDrive) to determine how much
herbicide to mix in 1 gallon of water for the various application
rates listed in rate recommendation section.
Table 1: Backpack or Other Small-Volume Sprayers
The amount of herbicide you need to add to each gallon of water based on the
recommended rate for target weed
GPA
Milestone®
7 fl oz/acre
Tordon® 22K
1 quart/acre
Tordon® 22K
2 quarts/acre
20
10.5 cc/gal
10 tsp/gal
3.2 fl oz/gal
30
7 cc/gal
6 tsp/gal
2 fl oz/gal
40
5.3 cc/gal
4.7 tsp/gal
1.7 fl oz/gal
50
4.2 cc/gal
3.7 tsp/gal
1.2 fl oz/gal
60
3.5 cc/gal
3.2 tsp/gal
6.3 tsp/gal
70
3 cc/gal
2.7 tsp/gal
5.5 tsp/gal
80
2.6 cc/gal
2.3 tsp/gal
4.7 tsp/gal
90
2.3 cc/gal
2 tsp/gal
4.2 tsp/gal
100
2.1 cc/gal
2 tsp/gal
3.7 tsp/gal
Tip
Use a syringe to measure herbicide if
you are applying a low-rate product like
Milestone®.
1 tsp = 5 cc
1/2 tsp = 2.5 cc
1/4 tsp = 1.3 cc
Table 2: OverDrive
The amount of OverDrive (dry formulation) to mix in
1 gallon to equal 4 oz product/acre
GPA
oz product
tsp
20
0.20
2.00
30
0.13
1.33
40
0.10
1.00
50
0.08
0.80
60
0.07
0.67
70
0.06
0.57
80
0.05
0.50
90
0.04
0.44
100
0.04
0.40
3 grams of OverDrive = 0.1 oz product = approximately 1 tsp
www.RangeandPasture.com
www.VegetationMgmt.com
Solutions for the Growing World
Trademark of The Dow Chemical Company (“Dow”) or an affiliated company of Dow
ForeFront HL and Milestone are not registered for sale or use in all states. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Tordon 22K is a federally Restricted
Use Pesticide. Always read and follow label directions.
R01-000-160 (05/13) DAS 010-58258
®™