Integrated Control Measures
Invasive non-native plants are a serious threat to native species, communities, and ecosystems in many areas around the world. They can compete with and displace native plants, animals, and other organisms that depend on them, alter ecosystem functions and cycles significantly, and promote other invaders. The good news is that many plant invasions can be reversed, halted, or slowed, and in certain situations, even badly infested areas can be restored to healthy systems dominated by native species. In most instances this requires taking action to control and manage the invasive plants. The goal of an effective weed management program is to replace undesirable plants that are causing loss (resource, economic, habitat, or aesthetic) with a plant or plants that are beneficial to the environment.

An integrated and coordinated approach to weed management should have two primary goals: First, development of a long-term plan that encompasses all land in a designated area, with all landowners and managers working together toward effective management; Second, implementation of the most effective, environmentally sound, and economical weed control methods for the target weed(s).

Integrated weed management (IWM) involves the use of the best control techniques described for the target weed species in a planned, coordinated program to limit the impact and spread of the weeds. The control methods selected should be determined by the control objectives for the land, the effectiveness of the control technique on the target species, environmental factors, land use, economics, and the extent and nature of the weed infestation. An accurate assessment of the target infestation will help determine the most appropriate control method or methods for the weed species. All control options have some limitations, and a multifaceted approach is going to move the control program further and faster than a single pronged approach.

Tilling/Cultural
Tilling is generally limited to cropland situations. Tilling can be effective against -rooted biennials and perennials such as diffuse & spotted Knapweed, but small fragments of some species, particularly those perennials with rhizomes, can often re-sprout following tillage. Some rhizomatous noxious weeds, such as leafy spurge or Russian knapweed, are not effectively controlled by tillage alone. Tilling should be completed before seeds develop and are shed onto the soil. The best control is achieved when the soil remains dry so that remaining plant fragments dry out. Moist soils help the fragments survive and re-grow.

Cultural methods of weed control that enhance the growth of desired vegetation may help slow invasion onto a site. The use of plant competition, smother crops, and crop rotation are methods most often suited to cropland agriculture. When dealing with noxious weeds, it is important to maintain the native or desirable vegetation in a healthy condition to allow adequate competition once the weeds have been controlled.

If tilling is your preferred choice of control the weeds must be tilled before flowering and re-vegetation must be a component when using this method.

Grazing with Sheep & Goat
Proper grazing utilization of native rangelands is vital to maintaining a healthy productive landscape; these native plant communities have evolved under grazing pressure for centuries from migratory herds of large grazing animals. Livestock use today is an important tool in maintaining healthy ecosystems, and they can be very effective in steep and rocky terrain. Controlled or strategic grazing by sheep and/or goats can be a highly effective weed management tool with precise application based on an understanding of plant-herbivore interactions. Effective grazing programs for weed control require a clear statement of the kind of grazing animal, timing, and rate of grazing necessary to reduce noxious plants and maintain healthy rangeland ecosystems. Using animals to graze is a high management option, as sheep and goats in particular need to be monitored closely to keep them within a targeted area. A successful grazing prescription should cause significant damage to the target plant, limit irreparable damage to the surrounding vegetation, and be integrated with other control methods as part of an overall weed management strategy. Sheep grazing is often the most economical and ecologically sound tool available to manage invasive plants such as established patches of leafy spurge. Sheep will not graze an area uniformly; consequently, a method should be employed to concentrate activities in a specific area. The primary function of a grazing management program is to halt seed production. Other multifaceted approaches should be integrated as well. Although sheep grazing will reduce density and biomass of noxious weeds, eradication does not occur.

Noxious weeds it works for: leafy spurge, spotted knapweed, Dalmatian toadflax, and Canada thistle. Animals have to graze before seeds mature to be effective with this method.

Herbicide Control
Herbicides are important tools for controlling noxious weeds. It is important to understand the effects and limitations of those used for control of noxious weeds. Herbicides are categorized as selective or non-selective. Selective herbicides kill a specific type of plant, for example, 2,4-D kills only broadleaf plants. Herbicides are also selective based on the rate used. Non-selective herbicides such as Roundup will kill all plants that come into contact with it. See herbicide labels for specific use guidelines that are pertinent to the land being treated.

Certain herbicides require licensing and training, and it is very important to follow all label and site restrictions when using these products. An herbicide is a tool that will create a weed-free window of opportunity. The success of a weed control program is determined by the management strategies which are applied following the application. A multifaceted approach might include proper grazing practices, re-seeding, hand pulling, and other integrated control methods.

For those who are concerned about the dangers of herbicide use, it is important to remember that these chemicals undergo stringent testing by the EPA, and they are designed to affect plant systems, not mammals. Most broadleaf herbicides are growth regulator products, meaning they accelerate cellular activity and respiration in broadleaf plants. When used according to label instructions, herbicides are very low in toxicity to fish, animals, and humans as well as the environment.

Successful Weed Management Principles for Herbicide Usage

Once the decision has been made to utilize herbicides as the method for control of noxious or nuisance weed species; there are 3 basic principles that need to be fundamentally addressed for successful applications. These standard principles are:

• Proper herbicide choice for the target species of concern
• Proper timing of herbicide application(s)
• Proper "consistent" application technique
• Additional site conditions/factors may also need to be considered to assure the most effective herbicide application out comes such as; soil type, slope, existing vegetation (target and non-target plants). Please contact a local weed management professional for technical assistance.

All state-listed noxious weeds can be treated and managed by herbicides at this time, please check with your local weed professional to obtain the proper herbicide and rate for your target species.

Hand Pulling
If you do not have a large infestation of noxious weeds, hand pulling may be a viable option, however, this technique can involve a great deal of labor and time. Breaking up the soil can cause further infestations, so care must be taken to minimize impacts on soil and make sure that all equipment and clothes are inspected for weed seed before moving into or out of the site. Annuals and noxious weeds with tap roots, such as spotted knapweed and houndstongue, are more effectively controlled with hand pulling. Perennial plants and those noxious weeds with extensive and/or rhizomatous root systems, such as leafy spurge or Russian knapweed, are not as effectively controlled with this method. When pulling weeds, it is highly advisable to wear gloves as some plants can cause moderate to severe skin irritation. Knapweed, for instance, contains toxins that can cause irritation to the skin. The key to hand pulling is to remove as much root as possible with minimal soil disturbance. With many noxious weeds, any parts of roots left behind can still be viable and sprout. The best method of disposing weeds after pulling is to put them in plastic garbage bags and take them to your landfill. Regarding concerns over spreading weeds at the landfill site, these bags are buried deep, the biological break-down process inhibits growth, and if they do manage to survive these first two components, weeds will be contained in a local site which most county weed districts monitor.

Noxious weeds can be-pulled in small patches (1/4 acre or less) with the exception of Canada thistle, leafy spurge, and perennial pepperweed and/or other rhizomatous rooted plants.

Biological Control-Insects
Biological control involves the use of living organisms, such as insects, to control a weed infestation, and attempts to recreate a balance of plant species with predators. Since many noxious weeds of most serious concern in rangeland are exotic species, they have few established natural predators. Bio-control research focuses on introduction of natural predators from the weed's area of origin onto local plant populations. Bio-control methods generally suppress host weed populations, but will not contain or eradicate them; therefore containment with another method is a critical component of this type of management. It is most effective on dense weed infestations over large areas. These insects are not adaptable to all sites; therefore evaluation must be used to find where they will be most effective. Contact your local weed professional for help with this type of management. Often bugs can be released for a nominal fee (if any) in your county through your county weed district. Leafy spurge currently has several insect species cleared for use in the United States, and Flea beetles (Aphthona spp.) seem to be showing the most promise at this time. Two gall flies and a seed head weevil and a root-boring beetle have established effectively on spotted knapweed in western Montana.

State-listed weeds that biocontrol agents are currently available for: Canada thistle, spotted knapweed, Dalmatian toadflax, tansy ragwort, St. Johns Wort, leafy spurge, purple loosestrife & diffuse knapweed. (* Currently APHIS has initiated research based biocontrol for salt cedar, with anticipation of approved permitting in the future.) For more information on biocontrol please contact Tonda Moon at tmoon@mt.gov.

Re-vegetation
Competitive desirable plants are an important part of successful integrated management of weed infestations because these plants occupy sites and use resources that weeds would otherwise use for growth and reproduction. In addition, desirable plants offer a benefit to the land owner. Unfortunately, weed infestations on highly degraded sites have no desirable plants to re-establish after weed control. These sites need revegetation. There are a number of conditions that must be addressed to insure successful establishment of desirable plants. Weeds must be controlled, as young seedlings do not have much chance of survival when they compete with well-established weeds. There needs to be a seed bed in which desirable plants can establish, and this can be accomplished by cultivation, a no-till rangeland or grassland drill, or an herbicide application. The plant species used for revegetation must be carefully selected to meet site conditions, climatic conditions, weed management objectives, and land use objectives. Broadcast seeding or using a drill is a method that can be used to get seeds into the soil. Timing of seeding is important to take advantage of available soil moisture and weed control, which is usually late fall or early spring. Finally, follow-up management should be designed to help the desirable plants and hurt the weeds. This could include mowing, herbicide application, or grazing by animals to target weeds.

When it comes to re-vegetation, it is imperative to control the weed problem first to give the native grasses and forbs a competitive advantage. Depending on the density and species of the infestation, not all sites will require re-vegetation. Contact local weed professionals for technical assistance or re-vegetation recommendations for your area.

To view re-vegetation help and research visit our library.

Burning
Burning can be used as a method of thinning decadent plant material to enhance other treatment options. In some instances, fire alone will give weeds an advantage over native plants. If you do decide to burn off the duff, most counties require a burning permit prior to a burn. More research is needed to determine whether fire is a viable weed control practice. (Taken from the NRCS Noxious Weed Quick Treatment Reference)

Education
Weed identification and early detection of new invader species are important tools in integrated weed management practices. Publications and computer programs are available that give excellent information and color plates of important weed species in the West through various organizations and agencies including your county weed board, your local weed management groups, MSU Extension, MDA, and the Montana Weed Control Association. Educational efforts targeting the general public emphasize what weeds are of concern and why they are a threat. These programs have included development of brochures which show hunters what spotted knapweed looks like in the fall, so they can report new infestations; a Ned and Nellie knapweed coloring book highlighting the damage that knapweed can do; bumper stickers, radio announcements, and tours of areas with serious weed problems which all emphasize the impact noxious weeds have on the land.

Mowing
Mowing reduces seed production in some plants. It is most effective on annuals before they flower and set seed, but timing and frequency of mowing varies with each specie. It has been shown that mowing can increase seed production in diffuse knapweed, while spotted knapweed can show a seed decrease when mowed in the flowering stage. However, in some species, re-sprouting occurs quickly and in large volume. Spotted knapweed has the ability to shorten its height and flower and set seed at lower levels after extended mowing. As a part of an integrated weed control program, mowing will remove large amounts of vegetation which then can allow for herbicide treatments. Remember after mowing, that it is important to gather up noxious weed flowers and seeds to prevent further infestations. Again, the best method of disposal is to bag weeds up in plastic bags and dispose of them at your landfill.

Some noxious weeds will respond to this method of treatment in that mowing reduces seed production, but it will not control the plants and can further spread infestation through dispersal of seed or plant parts.

Prevention
Preventing the spread of weeds by seed or roots should be the first line of defense in developing a weed management program. There are many potential weed threats to lands, and land managers need to be aware of the threat, identify unknown species, and implement effective controls immediately. Quarantines and embargoes can be effective in isolating and preventing the spread of weeds into new areas. Weed-free hay programs and certification programs for crops are designed to stop movement of new species into areas where they are not currently found. A program of this type is especially well suited for protection of wilderness areas where other control methods may be difficult to initiate if weeds become established.

The Montana Weed Control Association offers monetary rewards for those individuals who locate and identify new invaders. The new invaders that qualify for this incentive include: yellow star thistle, common crupina, rush skeletonweed, and dyers woad. The location and identity of the species must be confirmed by authorized personnel from either a local county weed coordinator or an MSU extension agent. In addition there are many Weed Prevention Areas (WPA's) identified in Montana. For more information on where they are located and what they entail, please refer to preventing weed spread.

The Do-Nothing Approach
So what happens if you are one of those folks who believes noxious weeds fall short on the priority list, and they cost too much money to prevent and control? Here are some facts to ponder on. . .

Noxious weeds are the number one threat to Montana's environment. Over the past 80 years, noxious weeds have covered over 8 million acres of this state. Currently, 27 noxious weeds are in existence on those 8 million acres. If left to spread, these non-native species alter ecosystems, reduce cropland and rangeland productivity, impact fisheries and wildlife habitat, and threaten survival of native species. Weed infestations that go unchecked eventually cause erosion and desertification of the land by first creating monocultures, where one specie wipes out everything else. Knapweed is rumored to produce its own toxin, a natural herbicide, to destroy other vegetation within its range. Canada thistle infests 1,526,803 acres of Montana, leafy spurge infests 1,027,419 acres, spotted knapweed infests 3,818,450 acres, and houndstongue infests 267,664 acres (although that figure is thought to be very conservative.)

Currently, financial resources are inadequate to effectively manage noxious weeds in Montana. It is estimated that $447.1 million dollars are needed to implement an effective and balanced weed program to reduce current spread by 5% per year. Knapweed alone costs Montana an estimated $42 million; money that could support 518 full time jobs in this state.

So the MWCA asks you to become an informed and educated citizen on the issues surrounding noxious weeds. Take pride in your land, take advantage of cost-share opportunities to help fund your weed control plan, and educate your neighbors on this worthy cause.