84
• 
Safety - page 25 • First aid - page 33 • Resistance management - page 41
Herbicides
How to Apply
:
Ground only.
Water Volume
:
Minimum 40 L/acre.
Application Tips
Care must be taken so as not to create overlaps in treated zones due to soil movement, which will result in excessive
Authority herbicide rates that could result in adverse crop response. All soil applications of Authority herbicide
require adequate rainfall for herbicidal activation.
Do not apply Authority (or any sulfentrazone products) in consecutive years. In case of drought in any of those years,
a subsequent application of Authority should be further delayed. Do not apply to soils classified as coarse-textured
soils. Do not apply in fine texture soils with less than 1.5% organic matter. Do not apply in any type of soil with an
organic matter content greater than 6%. Do not use on soils with a pH of 7.8 or greater. If using irrigation with water
that has a pH greater than 7.5, please review the label for adverse crop response. If adequate moisture from rainfall
or irrigation is not received within 7 to 10 days of application, a shallow incorporation no deeper than 5 cm may
be needed to obtain adequate weed control. Do not store the sprayer overnight or for an extended period with the
sulfentrazone spray mixture in the tank.
How it Works
Sulfentrazone controls weeds by the process of protoporphyrinogen oxidase inhibition (membrane disruption), a
mode-of-action commonly referred to as PPO inhibition. Sulfentrazone is primarily taken up by the roots of treated
plants.
Expected Results
Plants emerging from treated soil turn necrotic and die after exposure to light. Foliar contact causes rapid desiccation
and necrosis of exposed plant tissue. Shoot-root soil placement studies indicate that sulfentrazone is primarily
absorbed by the roots of the plant following soil applications.
Restrictions
Re-cropping restrictions
:
Alfalfa, barley, corn (field corn), wheat (spring and durum): 12 months after application;
winter wheat: 16 months; canola, corn (sweet and pop), sorghum: 24 months; lentils: 36 months.
For crops not listed above, a minimum rotational crop interval of 36 months must be observed and a representative
bioassay of the field must be conducted with the rotational crop and adequate soil moisture to evaluate potential crop
sensitivity.
Rainfall
:
Rainfall is required following application to activate the herbicide and for adequate weed control.
Grazing
:
Do not graze treated crops or cut for hay.
Pre-harvest Interval
:
Leave 60 days between application and harvest.
Environmental Precautions
Leave a 1 m buffer between the last spray path and water or wetland habitats and 10 metres to sensitive plants and
upland habitats when applying by ground. Buffer zones can be reduced by 70% when using shrouds and by 30%
when using cones mounted less than 12 inches from the crop canopy.
Toxicity
Oral (rats) LD
50
= 2,084 mg/kg.
Storage
Do not freeze.
Authority Charge (cont’d)