First herbicides with ESA-compliant herbicide label approved

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We don’t often write an eUpdate article when a new herbicide is approved by the Environmental Protection Agency (EPA). However, last week, the EPA issued a final decision to approve Liberty Ultra (glufosinate-P), making it the first herbicide with a label for agronomic crops that follows the principles outlined in the EPA’s Herbicide Strategy, which is intended to help herbicide registrations comply with Endangered Species Act requirements. You can learn more about the Herbicide Strategy in this recent War Against Weeds podcast. While this language will vary among products, the Liberty Ultra label provides somewhat of a template for what we should expect going forward. Specifically, the new language pertains to reducing off-target herbicide movement and pesticide use limitation areas (PULAs).

Key aspects of the Liberty Ultra label that pertain to reducing off-target movement are included in Table 1. Changes from the Liberty 280 SL label are indicated in bold.

All herbicides will require runoff mitigation points. The number of points required will vary for each herbicide. Mitigation options/practices are described in the EPA’s Mitigation Menu. Key aspects of the mitigation menu are summarized in Table 2. The EPA has developed a runoff points calculator that can help determine the number of points earned for practices already in place on your fields, including a ‘credit’ for certain counties that have relatively less runoff vulnerability. Table 3 lists the runoff mitigation relief points assigned to Kansas counties.

Table 1. Some examples of Liberty Ultra label requirements intended to reduce off-target herbicide movement.

Label Headings	Label Requirements
Mandatory Spray Drift Mitigations for Ground Applications	Do not exceed boom height of 24 in above target or crop canopy
Mandatory Spray Drift Mitigations for Aerial Applications	Spray boom must be mounted to minimize drift caused by wing tip or rotor blade vortices; Boom length must be 75% or less of wingspan and 90% or less of rotor diameter, unless wind is 11 to 15 MPH; If wind is 11 to 15 MPH, boom length must be 65% or less of wing span and 75% or less of rotor diameter; Do not release spray at height greater than 10 ft above crop canopy, unless necessary for pilot safety
Mandatory Spray Drift Mitigations for Aerial and Ground Applications	Wind speed and direction must be measured on location1; Do not apply when wind speed exceeds 15 MPH; Select nozzle and pressure that deliver medium or coarser droplets; During application, sustained wind speed must be between 3 and 15 MPH, measured at the release height or higher, in an area free from obstructions; Do not apply during temperature inversions
Mandatory Downwind Spray Drift Buffers2	50 ft for aerial application 10 ft for ground application
Ground Boom Spray Drift Buffer Reduction options	Reduced to 0 ft if: use a drift-reducing adjuvant; using a hooded sprayer; a windbreak or shelterbelt is present3
Aerial Spray Drift Buffer Reduction options	20% for coarse or coarser droplets; 35% for coarse droplets and a drift-reducing adjuvant; 50 to 75% for windbreak or shelterbelt4, can be combined with droplet size reductions
Mandatory Runoff Mitigation	Do not apply when soils are saturated or above field capacity; Do not apply during rain; Fields meeting certain criteria may not require mitigation; see Mitigation Menu5 to determine criteria; If criteria are not met, must achieve a minimum of three points for labeled uses6
Additional Runoff/Erosion mitigation	Must search Bulletins Live! Two within 6 months prior to application and follow instructions regarding use in a PULA
Endangered and Threatened Species Protection Requirements	Check Bulletins Live! Two within 6 months prior to application and follow directions and restrictions

¹ Predicted wind speed and direction for the application site should be acquired within 12 hours prior to application and should be reassessed every 15 minutes during the application.
Measuring wind speed and direction can be done by: instruments on the application equipment, anemometer, windsock, aircraft smoke system, checking behind spray rig.
²Spray drift buffers can include: Agricultural fields, roads, mowed grassy areas, bare ground, man-made structures with walls and/or a roof, vegetative filter strips, hedgerows, CRP lands, other items on the mitigation menu, provided herbicide does not degrade CRP habitat, managed wetlands, on-farm irrigation water resources not connected to adjacent water bodies.
³Windbreak or shelterbelt for 100% reduction with ground application must: run the full length of the treated area with no significant breaks; be sufficiently dense such that the non-managed area is not visible at the time of application; be planted according to conservation program standards and not include federal noxious species
⁴Windbreak of shelterbelt for 50% reduction with aerial application must: meet criteria for ground application plus: trees must be the same height or above the release height of the application; have a minimum of 1 row of trees/shrubs or a 4 ft wide strip of non-woody vegetation. A semi-permeable manmade structure can also be used.
Windbreak or shelterbelt for 75% reduction must: meet criteria for ground application plus: be at least twice as high as the release height of the application; have a minimum of 2 rows of trees/shrubs or at least 8 ft of non-woody vegetation.
⁵Runoff mitigation is not required if the field has: a perimeter berm system, an irrigation tailwater return system, subsurface or tile drains with a water control structure and controlled outlet; or if the application is: an injection, applied subsurface or under plastic mulch, a spot treatment, less than 1/10 of an acre; or if all areas within 1,000 ft down-slope are managed.
⁶Points assigned to various mitigation options are listed in Table 2. The number of points required will vary for each herbicide.

 

Table 1. Summary of Runoff/erosion mitigation measures and associated points. Applicators will be required to document how needed points are accrued for each application.

Mitigation Measures	Points
County-based mitigation relief7	0 – high vulnerability 2 – medium vulnerability 3 – low vulnerability 6 – very low vulnerability
Field characteristics
Slope < 3%	Mitigation not required
Sandy soils	Mitigation not required
Farm management practices
Tracking mitigation practices	1
Follow recommendation from a runoff/erosion specialist8 or Participate in a qualifying conservation program	1   or 2
Application parameters
Use an annual application lower than the maximum (but at least the minimum labeled rate)	1 – 10 to 29% reduction 2 – 30 to 59% reduction 3 – >60% reduction
Reduce the treated portion of the field	2 – 10 to 29% reduction 3 – 30 to 59% reduction 4 – >60% reduction
Soil incorporation (if not recommended on the label)	1
Measures applied in-field
Conservation tillage	2 – Reduced till 3 – No till
Contour farming	2
Vegetative strips	2
Terraces	2
Cover crops/ground cover	1 – with tillage 2 – short term, no tillage 3 – long term, no tillage
Erosion barriers	2
Irrigation management	2 to 3
Measures applied adjacent to the field
Grass waterway	2
Vegetative filter strips	1 – 20 to 29 ft wide 2 – 30 to 59 ft wide 3 – >60 ft wide
Vegetated ditch	1
Riparian area	1 – 20 to 29 ft wide 2 – 30 to 59 ft wide 3 – >60 ft wide
Wetlands	3
Habitat improvement area	1 – 20 to 29 ft wide 2 – 30 to 59 ft wide 3 – >60 ft wide
Filtering devices	1 or 3
Water retention systems	2
Subsurface drainage	1
One point is earned for using measures from more than one of: in-field measures, field-adjacent measures, water retention measures

⁷County-based mitigation relief points for Kansas counties are listed in Table 3. National information is available online in a list or map format.
⁸A runoff/erosion specialist is someone who has technical training, education, and/or experience in an agricultural discipline, water or soil conservation, or another relevant discipline that provides training and practice in the area of runoff or erosion mitigation and participates in continued education or training in those areas and has experience advising on conservation measures listed on the EPA’s mitigation website. Includes NRCS staff, Certified TSPs CCAs, CPAg, NAICC members, and Extension agents

 

Table 3. Runoff and erosion mitigation points assigned to Kansas counties based on runoff/erosion vulnerability.

County	Points	County	Points	County	Points
Allen	0	Hamilton	3	Pottawatomie	0
Anderson	0	Harper	2	Pratt	2
Atchison	0	Harvey	0	Rawlins	3
Barber	2	Haskell	3	Reno	2
Barton	2	Hodgeman	2	Republic	2
Bourbon	0	Jackson	0	Rice	2
Brown	0	Jefferson	0	Riley	0
Butler	0	Jewell	2	Rooks	2
Chase	0	Johnson	0	Rush	2
Chautauqua	0	Kearny	3	Russell	2
Cherokee	0	Kingman	2	Saline	2
Cheyenne	3	Kiowa	2	Scott	3
Clark	3	Labette	0	Sedgwick	0
Clay	0	Lane	3	Seward	3
Cloud	2	Leavenworth	0	Shawnee	0
Coffey	0	Lincoln	2	Sheridan	3
Comanche	2	Linn	0	Sherman	3
Cowley	0	Logan	3	Smith	2
Crawford	0	Lyon	0	Stafford	2
Decatur	2	Marion	0	Stanton	3
Dickinson	0	Marshall	0	Stevens	3
Doniphan	0	McPherson	0	Sumner	0
Douglas	0	Meade	3	Thomas	3
Edwards	2	Miami	0	Trego	2
Elk	0	Mitchell	2	Wabaunsee	0
Ellis	2	Montgomery	0	Wallace	3
Ellsworth	2	Morris	0	Washington	0
Finney	3	Morton	3	Wichita	3
Ford	3	Nemaha	0	Wilson	0
Franklin	0	Neosho	0	Woodson	0
Geary	0	Ness	3	Wyandotte	0
Gove	3	Norton	3
Graham	3	Osage	0
Grant	3	Osborne	2
Gray	2	Ottawa	2
Greeley	3	Pawnee	2
Greenwood	0	Phillips	2

 

 

Sarah Lancaster, Extension Weed Science Specialist
slancaster@ksu.edu

Frannie Miller, Pesticide Safety and IPM Coordinator
fmiller@ksu.edu

Tags:  label requirements herbicide EPA off target movement