Herbicides
283
• 
Safety - page 25 • First aid - page 33 • Resistance management - page 41
How it Works
Lontrel (clopyralid) is a systemic, hormone-type herbicide. It is absorbed by leaf and stem surfaces and is readily
translocated leading to swollen growing points and roots, cupping of leaves, twisted and distorted stems and leaves.
Maximum efficacy results from foliar application to young, actively growing plants. Solo is absorbed by foliage and
roots. It disrupts plant metabolism causing growth to stop. Works best under good growing conditions.
Expected Results
Plants will gradually stop growing and change colour, first to dark green and then to yellow before turning brown
as they die. Death of weeds may not occur until 14 - 21 days after application. With this lowest rate of Lontrel on
Canada thistle, some regrowth may occur by the end of the season, but this will not interfere with harvesting of the
crop. Solo causes susceptible weeds to stop growing within 24 - 48 hours. Yellow striping and purplish or reddish
discolouration of the leaves may occur. Leaves begin to die in 3 - 10 days starting with the youngest and moving to
the older leaves. Death of the plant may occur in 1 - 3 weeks.
Restrictions
Rainfall
:
Do not spray if there is a forecast of rain during or soon after application as the rain may
reduce control.
Re-cropping
:
Fields treated with Tensile can be seeded to barley, canola, flax, oats, wheat or summerfallowed.
Mustard can be seeded 2 years after treatment. Do not seed to crops other than those listed above for at least one year
after treatment.
Use of straw and manure from treated crops
:
Lontrel residues in straw may be harmful to susceptible plants. Do
not use straw from treated crops for composting or mulching on susceptible broadleaf crops. Manure can be spread
on fields that will be seeded to barley, flax, oats, canola (rapeseed), rye or wheat. Do not grow susceptible crops
such as peas, beans, lentils, potatoes, sunflowers or other sensitive crops on land that has been mulched with straw
containing Lontrel 360 residues within the last 12 months.
Grazing Restrictions
:
Do not graze treated crop or cut for feed within 20 days of application.
Environmental Precautions
Drift
:
Small amounts of drift may damage sensitive plants such as legumes.
Toxicity
Solo has low acute mammalian toxicity. Acute oral LD
50
(
rats) = 5,000 mg/kg. Non-toxic to fish, birds and bees.
Lontrel has very low acute mammalian toxicity. Acute oral LC
50
(
rats) = >2,000 mg/kg. Extremely low toxicity to
fish.
Storage
Store in heated storage; if product is frozen, bring to room temperature and agitate before use.
Thumper/Approve/Thrasher/Leader
Group 4, 6
Formulation
Product
Company
Active ingredient
Formulation
Container size
Thumper (PCP# 22659)
Bayer CropScience
Bromoxynil: 280 g/L +
2,4-
D: 280 g/L
Emulsifiable
concentrate
8
L, 128 L, 400 L
Approve (PCP# 28123)
Nufarm Agriculture
Bromoxynil: 225g/L +
2,4-
D ester: 225 g/L
10
L, 100 L, 500 L
Thrasher II (PCP# 30372)
MANA Canada
2
x 10 L, 120 L
Leader (PCP# 28853)
IPCO
10
L, 115 L, 450 L
Tensile (cont’d)