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Leafy spurge
Life cycle: Noxious statewide. Creeping perennial.
Leaves: Alternate, long, narrow, drooping, dark green.
Stems: 2 to 3 feet tall. Plant contains milky sap.
Flowers: Small green flowers surrounded by yellow-green bracts. Seed explodes from a three-celled capsule.
Roots: Dark brown with pink buds. May reach 20 feet deep.
Weed Species: state noxious weed
Comments: Difficult to control.
Control
Tordon 22K (picloram)
2 qt Tordon 2L (1 lb ae)
Spring or Fall. Primarily for small patches. Use 2 qt/A Tordon as a spot treatment. Rates above 1 qt/A cannot exceed 50% of an acre. Rates above 1 pt/A can be used in fallow cropland if the treated areas are less than 10% of the field. Tordon is an effective choice for leafy spurge. Minimum carrier is 20 gpa. The 2 qt rate will reduce the stand; however, additional Tordon or other follow-up is required. Some regrowth may be noted after application during dry seasons. Make spring treatments before seeds form. Make fall application before soil freeze-up. Tordon is also effective on hoary cress and Russian knapweed.
Tordon has foliar activity and extended soil residual. It controls topgrowth and translocates into roots. Rainfall is required to move the herbicide into the root zone. Trees, legumes, and broadleaf plants are very sensitive to drift and soil residues.
Tordon is registered for use in grass pasture and range, fallow cropland and noncrop areas. Bromegrass, buffalograss, and wheatgrass may be injured; bluegrass is tolerant. Tordon is formulated as a liquid containing 2 lb/gal acid equivalent.
RESTRICTIONS: Do not use in trees. Avoid drift to trees or sensitive broadleaf crops. For rates above 1 qt/A, do not harvest for hay within 2 weeks after treatment. Do not graze dairy animals for 2 weeks after treatment. Remove animals 3 days before slaughter if grazing within 2 weeks after spraying. Do not apply into water or wetlands or on inner banks of irrigation or drainage ditches. Risk of leaching is greatest where soils have rapid permeability (such as loamy to sand) and where the underlying aquifer is near the surface. Restricted Use Pesticide.
1.5 pt Tordon 2L + 1 lb ae 2,4-D ester (.38 + 1 lb ae)
Spring. Tank-mix. Intended as a 4 to 5 year program. Apply in late bud stage. Use Tordon at 1.5 pt plus 2,4-D ester at 1 lb ae/A. Lower rates may not provide sufficient residual control into the fall. Amine formulation of 2,4-D may be used if site limitations preclude ester formulations. Minimum carrier is 10 gpa for ground or 2 gpa for air. Intended as one application per year; some regrowth may be noted in wet seasons. Treatment has provided 75 to 80% stand reduction after 4 years. Promising program.
RESTRICTIONS: Do not use in trees. Avoid drift to sensitive broadleaf crops. Do not graze lactating dairy for 7 days after application. Labels for 2,4-D allow harvesting hay 30 days after application and require a 3 day removal period before slaughter. Refer to surface or groundwater precautions as for Tordon alone. Restricted Use Pesticide.
8-12 oz Plateau 2L (.12-.18 lb ai)
Several tree and shrub species listed on the label are known to have acceptable tolerance when applied under the canopy and/or to the foliage. Tolerance is based upon trees with a minimum of 2 inch DBH (diameter at breast height). Some species may exhibit tip chlorosis and minor necrosis. Foliar contact on some species may increase injury, defoliation, and terminal death.
RESTRICTIONS: Treated areas may be grazed. Do not harvest hay for 7 days after treatment.
Spring and Fall. Spring and fall application required each year. Selective, foliage applied, translocated herbicide. Uses for 2,4-D include grass pasture, range, and noncrop areas. Apply 2,4-D ester at 1.5 lb ae/A. Suggested carrier is 10 to 40 gpa. This treatment has been popular for large infestations; however, several years are required to achieve significant stand reduction.
Apply in spring at late bud stage when bracts begin to yellow. Retreat in September or early October when new fall growth is 4 to 6 inches. Results can be variable. One treatment per year prevents seed production. Stands have been reduced 50% in 3 years. Complete eradication is difficult even after 10 years. Surfactant or fuel additives increase leaf burn but seldom increase stand reduction.
Spring or Fall. Single application each year. Rates to 2 lb/A may be used in pasture and range; higher rates are allowed in noncrop and fallow. Control is less than for two applications of 1.5 lb/A each. Best for inaccessible areas where the labor cost for a second application is prohibitive.
RESTRICTIONS: Avoid drift to trees and sensitive crops. Not suggested for use in trees. Do not graze lactating dairy animals for 7 days after application. Labels for 2,4-D allow harvesting hay 30 days after application and require a 3 day removal period before slaughter. Note other label precautions. Labels for 2,4-D products vary.
.5-1.3 oz Telar 75XP (.023-.061 lb ai)
Spring.Apply .5 to 1 oz/A of Telar 75DF for hoary cress and 1.3 oz/A for Russian knapweed at bud to bloom stage in spring or in fall at rosette stage. Telar is labeled for use on noncrop and rights-of-way. Supplemental labeling includes use on pasture, range, and CRP. Several wheatgrasses, bluegrass, and smooth bromegrass are more tolerant to rates over .5 oz/A; bluestem, buffalograss, green needlegrass, Indiangrass, and switchgrass are tolerant to rates up to .5 oz/A. Minimum carrier is 10 gpa. Add NIS at 1 qt/100 gal.
RESTRICTIONS: There are no grazing restrictions for rates less than 1.3 oz/A. Labeling does not include hay uses. Do not apply to water, such as lakes, streams, or areas where runoff flows into such areas.
1-2 oz Escort 60XP (.038-.075 lb ai)
Spring. For hoary cress and Russian knapweed in grassland. Apply to actively growing weeds at rosette stage. Escort is for western range, rights-of-way, and noncrop areas. Minimum of 10 gpa carrier is suggested. Add NIS at 1 qt/100 gal.
RESTRICTIONS: Legumes will be injured. No haying or grazing restrictions for rates less than 1.66 oz; delay haying for 3 days for higher rates. Do not apply to water, lakes, streams, or areas that may run off into such areas.
Redeem (triclopyr + clopyralid)
4 pt Redeem 3L (1.12 + .38 lb a.e.)
Spring. Premix. For Russian knapweed. Apply 4 pt/A at early bud to early flower stage. Weeds must be actively growing. Minimum carrier is 10 gpa for ground or 3 gpa for air. Redeem is labeled for rangeland, grass pasture, CRP grass seedings, fence lines, and other noncrop areas. Redeem contains 2.25 lb triclopyr (Garlon) plus .75 lb clopyralid (Stinger) per gallon.
RESTRICTIONS: Do not graze or harvest forage for dairy cattle for 14 days after application. Do not harvest hay until next growing season for dairy or harvest hay for other livestock for 7 days after treatment. Remove meat animals at least 3 days before slaughter. Do not treat banks or bottom of irrigation ditches.
Tordon 22K + 2,4-D Ester (picloram + 2,4-D)
Plateau (imazapic)
Fall. Plateau is an imidazolinone herbicide used to control leafy spurge in pasture, range, noncrop areas, and CRP plantings. Plateau is being marketed only through public agencies and organizations. However, it is labeled and may be applied to private as well as public land. Results have been promising in SDSU tests; 70 to 90% control has been reported the year after application. Fall treatment to active growth has been more effective than spring applications. Plateau is available as a 2 lb/gal liquid.
Suggested rates are 8 to 12 oz/A of 2L. Use the higher rate for dense infestations that have been established for longer periods of time. The lower rate has been used in most tests. Field plot data suggest follow-up control programs are required to prevent reinfestation. Add MSO at 2 pt plus 2 pt/A 28% N. Minimum carrier is 10 gpa for conventional ground equipment or 2 gpa for low volume equipment. Grass tolerance is an important issue. Plateau is labeled as a seedhead growth suppressant for cool-season grasses. It also is labeled for range restoration to release native warm-season species such as bluestem, needlegrass, and Indiangrass using the same rates. It may also be used at 4 oz/A on certain species in new CRP seedings.
2,4-D Ester 1.5 lb ae 2,4-D ester 4L (1.5 lb ae)
Telar (chlorsulfuron)
Escort (metsulfuron)