Herbicides
191
• 
Safety - page 25 • First aid - page 33 • Resistance management - page 41
Application Tips
Weeds hardened off by cold weather or drought stress may not be controlled. Insufficient water volumes or coarse
sprays may also reduce control levels.
How it Works
Spike is absorbed by foliage and roots and inhibits cell elongation. 2,4-D is a systemic, non-selective herbicide
readily absorbed through leaves or roots. It is translocated primarily in phloem with the sugars but can also move
with water in the xylem. Accumulation is primarily in the young, rapidly growing meristematic regions of roots or
shoots. It inhibits pigments, including chlorophyll, leading to death.
Expected Results
Spike rapidly stops growth of susceptible weeds; however, typical symptoms (discolouration) of dying weeds may
not be noticeable for 1 to 3 weeks after application, depending on growing conditions and weed susceptibility.
Symptoms appear very rapidly (a few hours under bright conditions). Leaves of weeds take on a water-soaked
appearance, followed by wilting and necrosis. Susceptible plants become malformed before they die. Complete death
occurs within a few days.
Restrictions
Rainfall
:
If rain occurs within 4 - 6 hours after application, control may be reduced.
Grazing
:
Do not permit lactating dairy animals to graze fields within 7 days after application. Do not harvest or cut
treated crops for forage until 30 days after application. Withdraw meat animals from treated fields at least 3 days
before slaughter.
Re-cropping
:
No restrictions the year after treatment.
Environmental Precautions
Toxic to small mammals, birds, aquatic organisms and non-target terrestrial plants. Leaching: This product can move
in water where soils are permeable (e.g. sandy soil) and/or the depth to the water table is shallow.
Runoff
:
To reduce runoff from treated areas into aquatic habitats, avoid application to areas with moderate to steep
slope, bare soil, compacted soil or clay.
Toxicity
Spike has an acute oral LD
50
(
rats) = >5,000 mg/kg. Non-toxic to bees, birds and fish.
2,4-
D 700 ester: Moderate acute mammalian toxicity. Acute oral LD
50
(
rats) = technical 300 - 1,200 mg/kg. 2,4-D
formulations are toxic to small mammals, birds, aquatic organisms and non-target terrestrial plants.
Storage
Store in a cool, dry place and avoid excess heat. 2,4-D ester may be frozen.
Krenite
Group 27
Formulation
Product
Company
Active ingredient
Formulation
Container size
Krenite (PCP# 14064)
E.I. duPont Canada
Fosamine-ammonium: 480 g/L Water soluble liquid 10 L pack
Crops
Brush control on non-cropland areas - railroad, pipeline, utility and highway rights-of-way, storage areas, and
industrial plant sites.
KoAct (cont’d)