Integrated Pest Management - Noxious Weeds
IPM
What is a weed?
A weed is a pest!
Why should we care about weeds?
When they invade an area, many aspects of the environment and economy are 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 farming.
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 economy. Studies show that knapweed alone costs Montanans $42 million in lost tourism every year. This $42 million in lost dollars would support about 500 wellpaying 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 grazers eat the other
desirable plants first, leaving the weeds to flourish.
4. They are invader species. They are adapted to rapidly colonize disturbed areas.
5. They have allelopathy they give off chemicals that inhibit the growth 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? No one way completely works therefore, our best strategy is a mixed bag of methods used together. This is called:
INTEGRATED PEST MANAGEMENT (IPM)
The methods:
1. Prevention Keeping weeds out in the first place.
2. Chemical Using chemicals such as herbicides that control or retard the growth of weeds.
3. Cultural- Using practice such as controlled grazing, tilling, controlled burning, revegetation, hand pulling, etc..
4. Biological Control Using beneficial creatures such as insects or fungi that damage the weeds.
Prevention: Washing the undercarriage of the car to remove seeds. Using weed seed free hay to feed horses on pack trips. Not moving soil or gravel with weed seeds in it.
+ 1. Fast acting: Occurs even before the weed is present.
+ 2. Long lasting: If prevented, will not occur
+ 3. Environmental safety: These are all safe to the environment.
+ 4. Personal safety: Most prevention is quite safe.
+ 5. Effectiveness: Keeping weeds out works if we all work together!!
"An ounce of prevention is worth a pound of cure."
Chemical: Most commonly used herbicides (spray) to control Noxious Weeds: Tordon 22K, HiDep, 2,4D, 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 yearly. However, some types last many years in the environment (soil sterilants).
0 3. Environmentally safe: Herbicides need to be applied correctly, each person who wants to apply
restricted use herbicides needs to get her/his private applicators license. Improperly applied herbicides can be unsafe to the environment, but when applied correctly are a benefit to the environment as they control the noxious weeds that would otherwise cause vast environmental damage.
0 4. Personal safety: By following label directions and wearing Personal Protective Equipment (PPE) the risk to humans is minimal. The improper use of herbicides may cause harm to humans.
+ 5. Effectiveness: Herbicides used correctly, with proper timing, do control weeds well.
Cultural: -Mechanical tilling or plowing. -Hand pulling of the weed with all its roots. -Grazing sheep on leafy spurge to damage the leaves and stems and stop seed production. -Controlled burning a weed infested area to clear it for seeding of desirable plants.
+ 1. Fast acting: Most of these cultural methods show immediate results but do not always kill the roots.
- 2. Long lasting: Methods such as controlled burning, mowing or sheep grazing allow the weeds to grow back from the roots after the treatment is finished.
+ 3. Environmentally safe: Most methods are as safe as farming.
+ 4. Personal safety: Most methods are as safe as the farming practices that they are. However, be very careful with controlled burns, and wear gloves and be careful not to hurt your back when hand pulling weeds.
0 5. Effectiveness: This varies much with methods and weed species.
Biological: (Biological Control Agents) Releasing an insect whose larvae eat the roots of the weed. 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.
1. Fast acting: Biological control agents are often hard to establish. Once they do establish, their
population often takes many years to build up to levels where significant damage to the weed infestation can occur.
+ 2. Long lasting: Once established on a site, these agents will be there as long as the weed is present.
They will also spread (disperse) across property and political boundaries.
+ 3. Environmentally safe: Many biological control agents are ecological specialists. That means that they eat only one type of plant (the weed!) and often even feed on only one part of one type of plant. These agents have been rigorously scientifically tested to be sure that they are species specific 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 Eurasian habitats, they may finally work in many of our North American habitats.