(Herbicide) Applicators by Montana County ]
A weed is a pest! A weed is
any plant that grows where you do not want it to be. A noxious
weed causes environmental and/or economic damage.
Why should we care about weeds?
When they invade an area, many aspects of the environment and economy
affected. These include:
1. Decreased grazing for livestock and wildlife.
2. Decreased diversity therefore, decreased stability of the ecosystem.
3. Increased soil erosion.
4. Decreased water quality and fish habitat.
5. Decreased amount of food we can produce through ranching and
6. Decreased tourism.
Montana farmers and ranchers spend $100 million a year just to
control weeds. This money could be spent in other areas of the
Studies show that knapweed alone costs Montanans $42 million in
lost tourism every year. This $42 million in lost dollars would
500 well-paying jobs in Montana. (1)
Why are many weeds hard to control?
1. They produce many seeds and thus spread rapidly.
2. They have deep roots.
3. They are not palatable to livestock and wildlife therefore, these
eat the other desirable plants first, leaving the weeds to flourish.
4. They are invader species. They are adapted to rapidly colonize
5. They have allelopathy- they give off chemicals that inhibit the
of other plants.
6. They have waxy leaves so herbicides do not stick to the plant.
So, how do we control these unnatural, unwanted foreign invaders?
one way completely works therefore, our best strategy is a mixed bag of
used together. This is called:
INTEGRATED PEST MANAGEMENT (IPM)
1. Prevention- Keeping weeds out in the first place.
2. Chemical- Using chemicals such as herbicides that control
retard the growth of weeds.
3. Biological Control- Using beneficial creatures such as
insects or fungi that damage the weeds.
4. Mechanical- Tilling (plowing) or hand pulling the weeds.
5. Controlled Burning- Safely burning the weeds.
6. Grazing- Using grazing animals such as sheep or goats
eat the weeds.
7. Revegetation- reseeding a disturbed site to block or
0 = Neutral (mixed)
Positive - = Negative
As compared to the other methods.
-Washing the undercarriage of the car to remove seeds.
+ 1. Fast
acting: Occurs even before the weed is present.
-Using weed seed free hay to feed horses on pack trips.
-Not moving soil or gravel with weed seeds in it.
+ 2. Long lasting: If prevented, will not occur
+ 3. Environmental safety: These are all safe to the
+ 4. Personal safety: Most prevention is quite safe.
+ 5. Effectiveness: Keeping weeds out works if we all
"An ounce of prevention is worth a pound of cure."
-Most commonly used herbicides to control Noxious Weeds: Tordon 22K,
2,4-D, Banvel, Curtail, Transline, Escort and many others.
+ 1. Fast acting: Most herbicides show immediate results.
0 2. Long lasting: Most herbicides quickly break down in
the environment and need to be reapplied
However, some types last many years in the environment (soil
0 3. Environmentally safe: Herbicides need to be applied
correctly, each person who wants to apply
use herbicides needs to get her/his private applicators license.
can be unsafe to the environment, but when applied correctly are a
as they control the noxious weeds that would otherwise cause vast
0 4. Personal safety: By following label directions and
wearing Personal Protective Equipment (PPE) the
humans is minimal. The improper use of herbicides may cause harm to
+ 5. Effectiveness: Herbicides used correctly, with proper
timing, do control weeds well.
Examples: (Biological Control Agents)
-Releasing an insect whose larvae eat the roots of the weed.
- 1. Fast acting: Biological control agents are often hard
to establish. Once they do establish, their
-Releasing a round worm (nematode) or a mite that causes a gall
(swelling) on the plant.
-Infecting the weeds with specific fungi that damage that weed.
often takes many years to build up to levels where significant damage
+ 2. Long lasting: Once established on a site, these
be there as long as the weed is present.
also spread (disperse) across property and political boundaries.
+ 3. Environmentally safe: Many biological control agents
are ecological specialists. That means that
only one type of plant (the weed!) and often even feed on only one part
one type of
These agents have been rigorously scientifically tested to be sure that
feeders (i.e. are safe) before release.
+ 4. Personal safety: "They only bite weeds!"
+ 5. Effectiveness: In the long run, just as they keep
these foreign plants in check in their native
habitats, they may finally work in many of our North American habitats.
-Tilling (plowing) weed infestations to control the weeds.
pulling the weeds, along with proper disposal.
a weed infestation to allow more desirable plants to out compete the
+ 1. Fast acting: Plowing and hand pulling control the
0 2. Long lasting: Surviving roots and seeds left in the
soil can sprout. Remember, the seeds of some
can stay viable in the soil for up to 10 years. Therefore, the
and new sprouts pulled for 10 years!!
+ 3. Environmentally safe: Tilling and watering are
farming and gardening.
+ 4. Personal safety: Wear gloves when hand pulling to
avoid exposure to the toxins in some noxious
Be careful not to injure your back while stooping and pulling deep
+ 5. Effectiveness: When done consistantly and properly
tilling, hand pulling and watering can be very
Be sure to properly dispose of pulled plant (weed) matter so as to
in new areas.
burning an area infested with noxious weeds and then reseeding the burn
+ 1. Fast acting: Fire rapidly destroys the above ground
portion (tops) of most weeds.
0 2. Long lasting: Most fires do not get hot enough to
damage the roots or buried seeds of noxious
However, the stems, leaves flowers and seed heads can be severly
will quickly resprout after a fire. Infact, some noxious weeds
stimulated to produce
after a fire and also benefit from the nutrients released from the
of the fire.
+ 3. Environmentally safe: Northern Rocky Mountian and
plains ecosystems are well adapted to fire.
measures such as hand dug fire lines generally cause more damage than
+ 4. Personal safety: When done with the proper equipment
and personal, controled burning is quite
+ 5. Effectiveness: Many species of noxious weeds are
severly damaged by hot, properly timed fires.
sheep to graze a patch of leafy spurge just as it starts to flower can
and seed production. The sheep seem to "develope a taste" for the
goats onto a small area infested with spotted knapweed will cause them
to the ground.
+ 1. Fast acting: A large number of sheep and/or goats in
area can rapidly damage a weed patch.
- 2. Long lasting: When you take the animals out, the
noxious weeds can quickly resprout new tops.
+ 3. Environmentally safe: Well managed grazing is safe.
+ 4. Personal safety: Sheep and goats are generally save
+ 5. Effectiveness: Yearly grazing at the proper time can
severly damage foliage and seed production of
species. Be sure that enough time passes before you move the
to an uninfested
that seeds in the digestive tract have passed through the animal and so
seeds stuck to
(wool) have had time to fall off.
reseeding grasses and/or native plants after a controlled burn.
reseeding the ditches and banks of a new road. These desirable
that may sprout in these distrubed areas.
- 1. Fast acting: It takes a long time and healthy
ecological conditions for reseeded plants to compete
+ 2. Long lasting: Once established under healthy
conditions, desirable plants can compete with potential
+ 3. Environmentally safe: Planting native plants is
+ 4. Personal safety: Similar in safety to farming and
+ 5. Effectiveness: When done in a timely fashion and with
the correct plants for the site, these plants can
compete with many weed species.
(1) Schmidt, Lisa, Madison-Jefferson Extension
Agent, P.O. Box 1079, Whitehall, MT 59759, (406)287-3282.