November 2007

Livestock producers are becoming increasingly aware of various problem weeds. The presence or absence of these plants indicates the health of the pasture and hay land where found. Their presence usually leads to their increase and subsequent economic loss. Producers should realize that livestock will normally not consume these plants unless forced to.

Since these plants can be deleterious to animals or at the very least unpalatable (providing limited or no weight gains), it is important that producers be familiar with their identification, successful control or eradication methods, and ways to prevent further infestations.

Many persistent pasture weeds are herbaceous perennials introduced from Europe. When Western Canada was settled at the turn of the century, these plants were seeded by pioneers for both ornamental and medicinal purposes. With the abandonment of many homesteads over the years, many plants have spread beyond their original site into range, pasture and hay land.

Other plants are native to North America and have seized opportunities to invade disturbed soils, rangelands, tame pasture and haylands.

NOTE: Please be aware that this information is for educational purposes only. It is not recommended for medicinal and/or herbal purposes, as the information was gathered from a number of references and therefore not accurate.

Downy Brome (Bromus tectorum L.) and Japanese brome (Bromus japonicus L.)

Origin
Annual brome grasses are introductions from Europe that have been problem weeds in the winter wheat regions of the United States since the late 1800s. It is believed downy brome did not reach the Prairie region of Western Canada until the 1930s.

Description
Annual bromes grow as winter annuals, spring annuals or, rarely, biennials. Japanese brome may be more inclined to grow as a spring annual than downy brome. Growth is rapid, beginning very early in the spring and producing mature seed two months later around mid-June. At maturity, the whole downy brome plant has a purplish-red appearance, while Japanese brome is a pale tan. Downy brome often grows in large tufts. Downy brome resembles a miniature smooth brome grass plant except it is very pubescent. Stems are erect and slender. Even the swollen nodes on the stem are covered with soft straight hairs. The jagged ligule is one to three mm (1/8 - 1/4 in.) in length.  Japanese brome is very similar in appearance to downy brome in the vegetative stage except that it is more delicate.  Leaves of downy brome are two to four mm wide, whereas leaves of Japanese brome are one to three mm wide.

Once the inflorescence has emerged, there are both gross and specific characteristics that will distinguish downy and Japanese brome from each other.  The inflorescence is a many branched panicle which droops to one side. In downy brome, the panicle droops to an extent that the upper spikelets are pointed downward, whereas Japanese brome droop to a lesser degree.  There are five to 10 florets per spikelet in both Japanese and downy brome.  Spikelets of downy brome are two to three cm long and those of Japanese brome are one to two cm long and both are very hairy. The number of lengthwise parallel veins or nerves on the first and second glumes (outer-most layer of the seed) of each annual brome spikelet can also be used to distinguish the two species.  The first glume in downy brome has one nerve, vs. Japanese with three nerves.  The second glume in downy brome has three nerves, compared to that of Japanese brome with five nerves.  Each grey to purple coloured downy brome seed is tipped with a straight awn 12 - 17 mm (0.5 to 0.75 in.) long, whereas largely tan coloured Japanese brome seed has awns that are eight to 10 mm (0.3 to 0.4 in.) long and curve when mature so that they protrude at 90 degrees from the axis of the spikelet. 

Reproduction

By seeds only

Historical Use
None. Livestock, deer and antelope can get fair to good forage value out of annual bromes in spring prior to flowering. It actually is a major forage source in part of the north western United States, supplying the bulk of early spring forage for all livestock classes. It is the principal feed source on all spring lambing ranges and supplies good quality forage for a short term. Downy brome remains green and palatable for about a month in both spring and fall.  Japanese brome may remain palatable slightly later in the season.

Location
Annual bromes can be found in annual cropland, rangeland and industrial sites or waste areas. In undisturbed areas, they are typically an indicator of poor range condition. They readily invade where the native vegetation has been disturbed by overgrazing, fire, cultivation, etc. Since they do not compete well with perennial grass, it is not normally present in range in good condition. Annual brome has spread over native range, pasture land, disturbed soils and forests throughout the western United States.

In Canada, mixed populations of downy and Japanese brome can be found in southwestern Saskatchewan and Alberta, and plants can be found in isolated areas through to the Peace River in Alberta.  Manitoba has recently identified isolated fields with heavy infestations of each.

Mixed infestations of downy and Japanese brome are not uncommon in the brown and dark brown soil zones of Saskatchewan.  Japanese brome is adapted to somewhat moister habitats than downy brome and, as a result, has been reported in isolated populations in moister regions of the province such as Biggar, Liberty, Duval and Nipawin.

Concerns
Uncontrolled downy brome is a fire hazard and is extremely flammable, allowing fires to kindle and spread rapidly.   Range infested with annual brome species experiences a drastic shortening of the normal prairie fire cycle, resulting in a change of species composition that favours the persistence of annual bromes and other fire tolerant species.  The rough awns of downy brome can puncture the soft tissues of the mouth, nostrils and eyes of livestock; perforation of the intestines has also been reported. This occurs when livestock graze mature plants or consume hay with high proportions of downy brome. In the United States, the term "rip gut" is used when the seeds perforate the intestines and the animals die. The presence of awns also reduces feed intake.

Downy brome uses moisture from shallow layers in the soil. This directly influences the establishment of other desirable grasses, especially perennials.

Downy brome can contaminate fleece.

Control
Once annual bromes dominate an area it is difficult to eradicate, but eradication has been achieved in certain situations with diligence.  With a short lived seed, these plants must produce seed each year in order to perpetuate the infestation.  Therefore, to control infestations, it is imperative to prevent all seed production. Mowing large infested areas just as the majority of the panicles begin to emerge is one method to reduce seed set.

There are no herbicides registered in Canada to manage annual brome infestations in grass forages.  Trifluralin is available for establishing pure legume stands only.  Research in the United States has indicated that the Group One grass control products for broadleaf crops (Assure, Venture, Poast and Select) have provided good to excellent control of Japanese brome and suppression of downy brome at the highest labelled rates when applied while still in the seedling stage (prior to tillering or stem elongation).  Research is also ongoing on options for wheat.

In annual cropland, fall tillage is another method to stimulate the germination of seed in the fall, followed by spring tillage or glyphosate to control spring seedlings and over-wintered plants.

For smaller infestations hand-roguing is the best way to remove plants prior to seed set.  A pipeline company in the Swift Current area found that they eradicated a population from a significant length of right-of-way within a three to five year period using this method.  Note: If seed has already set prior to roguing, REMEMBER the seeds will work their way through woven poly bags, so line them with garbage bags first. When buying forage seed, make sure to ASK FOR and READ the certificate of analysis prior to purchase. Always request downy brome free seed and accept nothing less. Try to maintain pastures in good to excellent condition.

For herbicide rates, consult the provincial Guide to Crop Protection.

Origin

Native to North America and originally thought to be native east of the Continental Divide on the Great Plains.

Description
Curlycup gumweed is a coarse biennial to weak perennial from 30 - 90 cm (one - three ft.) tall. Many smooth stems grow from a deep tap root. Stubbendieck et al, 1989, report the plant as having an underground rhizome system. Root systems can reach depths of two meters (6.5 ft.). Curlycup gumweed is a herbaceous plant that belongs to the sunflower family. The dark green leaves are thick, oblanceolate (narrow ellipse or lens shaped) from one to four cm long and gummy to the touch. The leaf margins are closely toothed. Its showy yellow flowers are surrounded by numerous bracts at the base. The curved tips of these bracts are covered by a gum-like resin. Flowering occurs from July through September. Growth habit is erect with many branches coming off a single stem.  Seeds are achenes (like a sunflower seed).

Reproduction

By seeds and underground stems.

Historical Use
In early times, curlycup gumweed had medicinal uses. Spanish New Mexicans would drink an extract made from boiling three flower buds three times in three pints of water until only one pint was left. They would drink a glassful three times daily for kidney problems. Others used gumweed extracts to treat a wide range of ailments from skin troubles to rheumatic pains. Curlycup gumweed was used by the North American Indian people for various purposes: gummy secretions were used to relieve asthma, bronchitis and colic; a boiled extract of leaves and/or flowering tops relieved saddle sores and raw skin; it was consumed as tea in an attempt to cure tuberculosis; again as tea, to relieve coughs, as an expectorant and to treat dizziness.  The crushed flowers were used to make poultices for treating poison ivy.

The sticky sap was chewed as gum.

Leafless stems would be used as brooms.

In modern medicine, extracts of the leaves and buds are used to treat whooping cough and asthma.

Location
A common increaser throughout the entire non-wooded areas from western Ontario to British Columbia.  Sparse populations are found in Ontario and Quebec. It has been increasing in Saskatchewan, especially on the drier areas of saline flats and slough margins. Overgrazing of these types of areas definitely encourages gumweed. Plant populations increase under drought conditions.

Concerns
Because of its resinous coating, curlycup gumweed is not palatable to either livestock or big game. Some upland game birds will utilize the seeds. In dense infestations of curlycup gumweed, livestock are reluctant to graze between the plants, leaving some grasses ungrazed. Sheep, when hard pressed, will nip off a few flowers. Gumweeds can have toxic properties which to a large extent depend on the soil where they grow. This is especially true for curlycup gumweed. When excessive selenium is absorbed, the plant becomes poisonous.

Control
Gumweed does not tolerate frequent disturbance, and is therefore rarely a problem in annual crops.

No herbicides appear to give consistent results. Herbicides containing 2,4-D or MCPA are labelled to provide top-growth control at 560 to 840 g per ha (8 to 12 oz. per acre) of active ingredient.  The Canadian label for Restore (aminopyralid + 2,4-D) states that the product will provide top-growth control only, and the label for the equivalent product in the United States claims control at the same rate.

Good grazing management will prevent populations of gumweed from increasing. Avoid overgrazing sloughs and slough-like areas.

Origin
From Europe. Grown in gardens for its medicinal properties.

Description
Absinth is a perennial with a strong pungent sage odour. It has a shrub-like appearance. Plant height ranges from 0.7 - 1.2 meters (two - four ft.). Plants re-grow every spring from existing crowns. The leaves are 5 - 10 cm (two - four in.) long, divided many times into ovate to oblong segments, grey to olive green in colour and covered with fine hairs when mature. Leaf arrangement is alternate. Lower leaves have long petioles; upper leaves have short petioles. Upper leaf blades are less lobed. The numerous flowers have either yellow or purple florets, are very small, one to two mm (1/8 in.) long and are borne on spike-like panicles. They are grouped into heads on the upper leaf node. The base of the flowers is hairy and borne on stalks. The plant flowers from late July to September.

Seeds are very fine, narrower at the base, hairless and brownish in colour.

Reproduction
From numerous seeds.  Short rhizomes will expand the crown but the plant only reproduces vegetatively if crowns are split by field operations and moved.

Historical Use
Absinth was commonly used in the 16th century for medicines, ritualistic ceremonies, folk remedies and charms. It was believed to have mystical powers, so was widely used by magicians, witches and others who practiced the occult.

Distillates of absinth caused hallucinations and stimulation of the body, making it a much desired drug by both sophisticates and artists. The famous artist Van Gogh was reported to be severely addicted to the drug. The Swiss used absinth to make home brew. This practice ceased in 1908 as the brew was very intoxicating and the side effects very unpleasant.  Some sources suggest that at least some of these side effects can be attributed to the high alcohol content or the copper sulphate used for enhanced colouring.

In 1543, absinth was considered a medicine to be used in steam baths to break up gallstones, enhance fertility, restore memory, induce abortions and shake off travel fatigue. In general, absinth was consumed as a health conditioner and a digestive organ stimulant. In the Middle Ages, people carried it while they traveled to keep dangerous animals away. In the early 1900s, Americans who collected absinth were paid four cents per pound of dried leaves.

Young flowers yield aromatic oil which is used to prepare vermouth and absinth.

In Europe, it is still considered a valuable herb for the medicine world.

The leaves are used as a sage-like herb.

Location
Absinth is found in dry soils, overgrazed pastures and rangelands, waste places, ditches, ravines, borrow pits, gravel piles and fence lines. It is most noticeable on fence lines and roadsides. Absinth is found throughout Canada, but it is most abundant on the Prairies.

Concerns
Absinth taints dairy products if present in either pastures or hay eaten by dairy cattle. Cattle will not graze it by choice. In hay, absinth would be consumed inadvertently. It spreads rapidly in overgrazed pastures. Once established, it is very difficult to eradicate. Stored grain can become tainted by absinth seed or leaves which in turn taint flour and other grain products.

Because its pollen is wind borne, absinth, like the other Artemisia species, can cause hay fever. Its odour can cause great discomfort to sensitized persons, especially those working close to absinth infested areas.

Control
Absinthe does not tolerate frequent disturbance, and is therefore rarely a problem in annual crops.

Mowing prior to the plant setting seed helps control its spread. Seed production is only reduced as the plant then sends out horizontal stems that will also set seed. Hand weeding, though labour intensive, works effectively to control smaller areas. It is especially important to dig out all the roots if possible. By not overgrazing, forages and pastures remain healthy and less subject to invasion. It is harder for invaders to take over a healthy range.

For herbicide control, consult the provincial Guide to Crop Protection.

Origin
An ornamental introduced from Europe; originally planted by pioneers in gardens.

Description
This coarse, aromatic perennial has many tall stems, 0.7 - 1.2 metres (two  to four ft.), growing from rhizomes. The leaves are pinnately divided (several segments occurring at regular intervals along opposite sides of a common mid-vein) with each dark green leaflet being narrowly toothed. Some of the lower leaves reach 30 cm (12 in.) in length. There are numerous glands on the leaflets which emit a strong, rank odour when crushed. The slightly ridged stems are topped by numerous deep yellow button-like flowers that are approximately six mm (1/4 in.) in diameter. Between 20 - 200 flowers make up the flat topped cluster. Flowering occurs in August. Seeds are achenes.

Reproduction
From seeds and, to a limited extent, short rhizomes slowly expand the clump.

Historical Use
Boiled and/or steeped, tansy was used for laxative purposes, in topical dressings and for its internal healing properties. Tansy was used in small doses to treat jaundice, dyspepsia, colds, fevers, hysteria, worms and nervous disorders for women. Externally, compresses of tansy tea were considered excellent for swelling, tumours, inflammations, sciatica, bruises, freckles and sunburn. In large doses, it can be toxic. In earlier years, it was used by Newfoundland women as an insect repellent. They would tuck leaf pieces under their head scarves to keep insects from biting while they worked outside.

References report tansy has been used commercially as an insecticide.

Location
Throughout Canada with many locations throughout the Prairies. Tansy is prevalent along fence lines. Since it was, and still is to some extent, a garden plant, it is commonly spotted in abandoned farm yards, hedgerows, fence lines, waste ground and roadsides.

Concerns
Although generally not a problem in cultivated crops, it will behave as an increaser in overgrazed pastures. Once in pastures, it can lead to abortions or death if livestock eat it due to a shortage of suitable plants.

Control
Tansy does not tolerate frequent disturbance, and is therefore rarely a problem in annual crops. Keeping pastures and forage stands in good condition will help prevent tansy invasion.  It is suspected that mature stems remaining erect through the winter can aid tansy spread as seeds shatter and drift over packed snow.  Cutting tansy immediately following flowering will help to reduce spread to new areas.  Several potential biological control agents have been documented in Europe.  A consortium of Canadian provinces and U.S. states have accessed funding to investigate their viability for introduction to North America.

For herbicide control consult the provincial Guide to Crop Protection.

Description:
This coarse, aromatic perennial has many tall stems, 0.7-1.2 metres (2 - 4 ft), growing from rhizomes. The leaves are pinnate (similar to rose leaves) with each dark green leaflet being narrowly toothed. Some of the lower leaves reach 30 cm (12 in) length. There are numerous glands on the leaflets which emit a strong, rank odour when crushed. The slightly ridged stems are topped by numerous gold button-like flowers that are approximately 6 mm (1/4 in) in diameter. Between 20-200 flowers make up the flat topped cluster. Flowering occurs in August. Seeds are achenes.

Reproduction:
From seeds and to a limited extent rhizomes.

Historical Use:
Boiled and/or steeped, tansy was used for laxative purposes, in topical dressings and for its internal healing properties. Tansy was used in small doses to treat jaundice, dyspepsia, colds, fevers, hysteria, worms and nervous disorders for women. Externally, compresses of tansy tea were considered excellent for swelling, tumours, inflammations, sciatica, bruises, freckles and sunburn. In large doses, it can be toxic. In earlier years, it was used by Newfoundland women as an insect repellent. They would tuck leaf pieces under their head scarves to keep insects from biting while they worked outside.

References report tansy has been used commercially as an insecticide.

Found:
Throughout Canada with many locations throughout the Prairies. Tansy is prevalent along fence lines. Since it was, and still is to some extent, a garden plant, it is commonly spotted in abandoned farm yards, hedgerows, fencelines, waste ground and roadsides.

Concerns:
Though not a problem in cultivated crops it will behave as an increaser in overgrazed pastures. Once in pastures, it can lead to abortions or death if livestock eat it due to a shortage of suitable plants.

Control:
Keeping pastures and forage stands in good condition will help prevent tansy invasion.

For herbicide control consult the provincial Crop Protection Guide.

Origin

Native to Europe and Asia.

Description
Leafy spurge is an erect perennial plant growing from deep creeping underground rootstocks. Quick to emerge in the spring, it can reach heights of one metre (three ft.). All parts of the plant contain a milky white sap. Numerous simple, linear shaped leaves are alternately arranged on the lower stem. A few scattered hairs are found near the top of the otherwise smooth stems. A whorl of leaves is located at the base of the inflorescence. The inflorescence is a cluster (umbel) of small inconspicuous yellow-green flowers and a pair of bracts surround each flower cluster. Flowering occurs late June through July. The seeds, grey green, yellow or brown in colour, usually have a yellow bump near the base. Three seeds are found per capsule. The creeping roots are red in colour and woody. They are covered with a thick bark which enables them to resist decay. New plants will develop from the numerous root buds.

Reproduction
By both seed and creeping roots. Since it can reproduce from root fragments up to one metre (three ft.) deep in the soil, control is difficult. Seed production is low - approximately 140 seeds per plant. Seeds are ejected from the capsules when ripe.  Brown, grey-brown, grey and mottled seeds are able to germinate, but seeds that are reddish brown to orange and yellow are not viable.

Historical Use
None known.

Location
Leafy spurge is aggressive in undisturbed areas such as pastures and roadsides, especially on sandy and marginal soils, and is considered a severe perennial weed in the Northern Great Plains of the United States and prairie provinces on untilled non-cropland sites.

Concerns
In Canada leafy spurge infestations increase yearly. The extensive creeping root system stores ample food reserves which aid root buds in establishing new plants. The roots can remain viable for the first six years of the plants life. The sticky latex prevents grazing by many animals. Literature reports that the carrying capacity of pasture land will drop to near zero with more than 20 per cent leafy spurge cover, since cattle refuse to graze amongst spurge plants.

The toxic property found in the latex of leafy spurge when taken internally can cause scours, weakness, and occasionally even death. External contact can result in dermatitis and even blistering in animals and people.  It has been reported that horses that walk through freshly mowed areas of leafy spurge will develop blisters and lose the hair above their hooves. Sheep may consume up to 60 per cent of their diet as leafy spurge and goats may consume up to 90 per cent of their diet as spurge, making them candidates for integrated control of leafy spurge. Cattle and horses learn to avoid eating the growing plants. Most animals will eat leafy spurge plants found in hay.

Control
Leafy spurge does not tolerate frequent disturbance, and is therefore rarely a problem in annual crops.

Many weed managers have adopted a strategy of "early detection and eradication" of new infestations in combination with "containment and Integrated Control" of established stands in order to prevent the spread of invasive weeds such as leafy spurge.  Eradication of well established stands is impractical if not impossible, but eradication of new infestations by intensive herbicide treatment is possible and part of an effective strategy to prevent spread of the weed.   

Once populations are well established and eradication becomes impractical or cost prohibitive on a large scale, management priorities switch to containment and integrated control.  Containment requires that a perimeter boundary be established and maintained so that any plants emerging outside of the containment zone are quickly eradicated using similar herbicide techniques to the eradication priority.   Within the containment zone, integrated management methods, such as biological control, sheep grazing, mowing, burning, etc., are used together to reduce the impact of the weed on the contained area.  This general strategy can be applied to many other invasive plants.

Several biological control agents have been screened and released in North America for the suppression of leafy spurge.  The Apthona sp. flea beetle has been the most successful.  There have been three species of Apthona that have been introduced, each with their own habitat requirements.  The black dot (brown body), brown dot (brown body) and black (bodied) beetles are progressively adapted from hot, dry, sandy sites (black dot beetle) through to warm, moister, loamy soils with increasing amounts of soil cover (black beetle).  Excessive cover will impede the effectiveness of even the black beetle.  Other methods used in conjunction with beetles should avoid their vulnerable egg laying period from early June to late July. 

Sheep and goats have been used in programs to try to control leafy spurge by browsing. On pasture land, close grazing with sheep will give good control. Sheep will graze the spurge ahead of the grass if the spurge plants are young.

Burning can open up densely covered soil to allow access by either beetles or herbicide, but can increase the germination of spurge seedlings as well. 

For herbicide control, consult the provincial Guide to Crop Protection.

Scentless Chamomile (Matricaria perforata Mérat)

Origin
Introduced from Europe as an ornamental.

Description
This fibrous rooted plant can act as either an annual, winter annual, biennial or short-lived perennial. When overwintering occurs, large bushy plants result. Plant heights reach 15 cm to 1 m (6 to 39 in.). The light green leaves are alternate in arrangement, stalkless, very finely divided and smooth. Scentless chamomile plants have hairless stems with many ascending branches that are topped with daisy-like flowers. These have raised yellow centres surrounded by white petals and are two to four cm (3/4 - 1 1/2 in.) in diameter. Flowering occurs in late June through September. Crushed flowers are practically odorless as compared to wild or German chamomile (Matricaria recutita) which smells strongly of the herbal chamomile tea. The seed is a small ribbed, dark brown achene.

Reproduction
Scentless chamomile can produce from 300,000 to 500,000 seeds per plant or 1,000,000 seeds per square meter of densely infested area. Seeds are easily spread by wind and water. Seeds are dark brown in colour and are light in weight, thus the common areas of infestation tend to be around water sources where seeds have been floating.

Historical Use
Scentless chamomile was used for ornamental purposes only.  While not poisonous, it has little feed value.

Location
In all provinces throughout Canada, particularly in headlands, waste areas, ditches and forage crops. It has an extensive, fibrous root system enabling it to cling to large clumps of soil, making it possible to survive cultivation especially in both heavy and solonetzic soils. Scentless chamomile grows best in high moisture areas, spreading rapidly during wet periods.

Concerns
Scentless chamomile can germinate in soil that is completely flooded. When invading a new area, it often begins growth around stream banks, flooded ditch bottoms or slough edges. From newly invaded areas, it moves to other disturbed areas such as transmission lines, pipelines, newly constructed roads, right-of-ways and drainage ditches, finally invading forage stands, native pastures and cultivated fields. Scentless chamomile seeds will survive in the soil for long periods (up to 10 to 15 years), but most will germinate in the first three to four years after being shed. Seeds requires light to germinate. Therefore, frequent tillage may promote infestations.

Its coarse, rank growth is unpalatable to livestock. It increases especially in overgrazed conditions. Plants that over-winter are very difficult to control as they mature early and the adjacent vegetation cannot offer much competition. Since scentless chamomile responds so well to moisture, a wet year means more contaminated feed and larger yield losses. Field work done when moisture levels are high would serve to transplant the weed.

Control
Mowing non-cropped areas often prevents seed production. In most years, multiple mowings will be needed.  Mowing promotes scentless chamomile to flower below the cut line, therefore a strategy of mowing that begins at the highest possible cut height with each cut made progressively lower will be more effective at reducing seed production.

A solid healthy stand of forage will help to suppress scentless chamomile growth and establishment. Seeding to smooth bromegrass for several years should reduce the infestation.  Several years of alfalfa production has been shown to reduce scentless chamomile populations.  Cut forage crops prior to chamomile petal emergence to prevent production of viable seed.

Since scentless chamomile seeds are spread easily by farm equipment, moving water and snow make sure to thoroughly clean equipment when moving to a different field. Tarping loads of grain and bales when transporting helps to prevent the spread of scentless chamomile seeds. Summer and winter road maintenance equipment will further the spread of scentless chamomile.

Hand pulling, hoeing and tillage are effective on small areas. These methods are most effective when performed before scentless chamomile flowers.

Classical biological control agents are available for heavily infested areas.  The scentless chamomile seed head weevil (Omphalapion hookeri) is a tiny black weevil that lays it eggs in the flowers prior to petal emergence and larva consume developing seeds.  Feeding continues until the larva pupates and eventually emerges from the flower as an adult which over-winters in the trash on the soil surface.  The scentless chamomile gall midge (Rhopalomyia tripleurospermi) lays eggs in the growing points of the plant where irritation to undifferentiated tissues results in the formation of a gall to enclose and protect the developing midge larva, instead of normal stem, leaf or flower tissues.  The adults only survive for 24 to 48 hours outside of the gall, and this insect will produce one to three generations per year.  The insect over-winters in the galls.  A third agent, the scentless chamomile stem boring weevil (Microplontus edentulous), lays eggs on the stem of scentless chamomile and larva burrow within the soft pith inside the stem, then pupates and matures inside the stem where it over-winters and emerges as an adult in the spring

Both the seed head weevil and the gall midge have become well established in Saskatchewan, but the stem boring weevil has not been very successful. 

For herbicide control, consult the provincial Guide to Crop Protection.

Baby's-Breath (Gypsophila paniculata L.)

Origin
Introduced to North America from Europe and Northern Asia.

Description

An erect growing perennial with many branches on one stem. Plant height ranges from 30 - 90 cm (one - three ft.). Leaves located at swollen nodes are dark green to silver in colour, narrow, smooth and opposite each other on the stem. Lower leaves can be 10 cm (four inches) long and upper ones up to 2.5 cm (one inch) long. Both clasp the stem. Plants appear to be covered with a bluish waxy bloom. Flowers vary in colour, from white to pale pink. These flowers, which are six mm across (1/4 in.) and numerous, are found on the ends of branches. This gives the plant a light, fluffy appearance. Flowering occurs from July through September. Four black seeds covered with concentric rows of bumps are found per black capsule.

Reproduction
By seeds only. Once established, the roots can store enough food reserves to ensure the plant's survival of two or more years.

Historical Use
As a garden ornamental. It was a common plant used in bouquets at funerals and weddings. Today, it is a common plant in dried flower arrangements.

Location
Baby's-breath grows in waste areas, roadsides, hayfields and pastures. It prefers sandy soils where it roots deeply to ground water.

Concerns
This garden escapee is a prolific seed producer. It persists in areas of submarginal sandy farmland where either tame or native grasses have been overgrazed, leaving bare patches. However, there are many infestations in undisturbed areas.

Control
Baby's breath does not tolerate frequent disturbance, and is therefore rarely a problem in annual crops. Using heavy grazing early in the spring will help to reduce seed production and the subsequent spread of the plant. Mowing produces similar results, but remember that it will not control the existing plants.  Flaming the crown of each baby's breath plant with a torch has been found to control a high percentage of plants.

For herbicide control, consult the provincial Guide to Crop Protection.

Toadflax (Linaria vulgaris Mill.)

Origin
Toadflax came from Eurasia. Other names for toadflax are butter-and-eggs, yellow toadflax and wild or perennial snapdragon.

Description
This perennial plant has extensive creeping roots. The stems range from 20 - 80 cm (eight - 31 in.) in height and are green, hairless, and un-branched. They are covered with numerous leaves. The leaves are hairless, virtually stalkless and 2.5 - seven cm (one - three in.) long, six mm (1/4 in.) wide with the narrow part of the leaf at the base. New shoots produced in clumps are found narrowly spaced along the lateral creeping roots giving the plant a bushy appearance. (Note: A broadleaved species, dalmatian toadflax (Linaria dalmatica), is also found in Saskatchewan but is not common, being associated mainly with abandoned yard sites.) Toadflax flowers are shaped like a snapdragon, have a long spur that points backwards and are half the length of the flower. Flower colour is mainly butter yellow with the petal tips of the petals more orange. Flowering occurs from June to October. Seeds are flat, somewhat circular in shape, warty in texture, brown/black, very small and broadwinged. One toadflax stem is capable of producing 5,000 seeds. Unlike leafy spurge, yellow toadflax does not contain milky sap.

Reproduction

Creeping roots and seeds.

Historical Use

When first introduced to North America, toadflax was grown for ornamental and medicinal purposes. However, the weedy potential of the plant was soon recognized.

Toadflax was commonly used in folk medicine and homeopathy. In the Middle Ages it was specifically used to treat throat ailments, especially scrofula or tuberculosis of the neck, causing enlargement of the lymph glands of the neck, a very feared disease of those times. It was used to heal ulcers, carry away the water of dropsy, plus remove liver and spleen obstructions. When combining toadflax with lupin powder, citizens of the 16th century believed they were healing scurf, leprosy, skin spots and pimples, wheals and morphea. Extracts with water were thought to remedy the heat, eye inflammation and redness.

Chopping up the whole herb plant and combining it with grease from an old hog was thought to cure piles, ugly sores and other skin eruptions.

The 16th century people also believed toadflax to have mystic powers especially when combined with the number three. Stringing three toadflax seeds on a linen thread was thought to be so potent it would protect the wearer from all evil. An evil spell cast upon you could be broken simply by walking around a yellow toadflax plant three times.

In more modern times, budding plants have been used for astringents, and treatments of jaundice, liver troubles and various skin diseases.

Toadflax was made into a lotion to treat insect bites. This practice was done in both England and New England. Other uses were as fly repellents over doors before the days of screens and flypaper.

Settlers would boil toadflax plants in milk and pour the liquid into saucers to poison flies.

Toadflax was a major source of yellow dye. This would have been its most common use. Once chemical dyes came on the market, this use was discontinued.

Location This escaped ornamental has naturalized throughout North America. It is a very destructive weed found along roads, railways, rangeland, forage stands, pastures, mountain meadows, disturbed soils, waste areas and cultivated land.

Concerns

Toadflax has toxic chemical compounds poisonous to cattle. Usually cattle dislike both its taste and odour, so poisonings from grazing are rare.

Hay with a high toadflax content has the potential to cause poisoning, as cattle have more difficulty avoiding the plant in hay. Agriculturally, this plant is a menace because it is a prolific seed producer. The seeds can survive in the soil for up to three years. They can be transported by water, wind, machinery, feed, birds and animals.

Its creeping rootstocks can increase radially up to two m (six ft.) if left in untilled summerfallow.  This feature, together with its prolific seed production, enables it to rapidly invade over-utilized areas.

Control
In crops, thorough cultivation helps to control toadflax to the point where next year's yields will not be reduced.

Crop tillage can hold toadflax in check. This works most effectively in summerfallow where cultivation is done when flowering commences. When new growth is observed, make sure to cultivate again within eight to ten days or when new shoots reach 10 cm (four in.). Note: This will promote the germination of viable toadflax seeds found in the soil. Broken root pieces will send up new stalks also. With continued summerfallow, both new plant sources should be eliminated. Take care to clean tillage equipment when moving to another field to avoid furthering the infestation. (Caution: excessive tillage could cause soil erosion.)

Pre-harvest glyphosate can be used to control toadflax when terminating hay grain or in crops where the practice is registered.

It has been observed that crested wheatgrass will check the spread of toadflax but never eradicate it totally. Use the crested wheatgrass for hay, pasture and forage stands. A healthy stand is important so it can compete with the weed.

Mowing to prevent seed production is a useful tool.

Research on biological control using insects is ongoing, with limited results to date. Large toadflax infestations have been reduced considerably by flower feeding beetles in the 1950s. Some areas in northwestern Saskatchewan still experience large toadflax populations.

For very small patches of toadflax, hand pulling every three to four weeks beginning in June will help control but not eliminate the plants.

In rangeland, chemical control is practical. Spot treatments with Tordon 22K has worked effectively (95 per cent control). This chemical can be used throughout the growing season, but patches are more visible and thus easily treated if applied at the flowering stage. Note: The active ingredient in Tordon 22K is picloram, which does not readily break down. It may persist for more than five years. It also is soluble in water, moving easily through the soil to the water table. Therefore, it is not a chemical to be used on coarse sandy soils. Often, it is the sandy soils where large toadflax populations persist.

For information on other herbicide control methods, consult the provincial Guide to Crop

Producers should follow a weed or invasive plant strategy that includes prevention, early detection and eradication, and containment and integrated control.  Prevent the introduction of new weeds.  Monitor to detect new introductions early and eradicate using hand pulling or herbicides.  If invasive weed problems become too large to successfully eradicate, then they should be contained and not allowed to spread using a boundary buffer zone, while integrated management methods are applied within the containment zone to reduce the negative impacts of the invasive weeds.  Below are some useful tips for activities to fit into your integrated plan:

1. Be able to identify the plant.
2. Review present management techniques.
3. Walk and check fields - windshield surveys are not accurate indicators, as the extent of the infestation often goes undetected.
4. Avoid equipment contamination - clean tillage and haying equipment between fields; also clean road maintenance equipment.
5. Tarp grain trucks or otherwise contain weeds to the vehicles that grain or forage is moved in.  Plastic wrapping of bales to be moved long distances is a viable alternative.
6. Purchase clean seed and feeds. Make sure to thoroughly read the field inspection sheet prior to forage seed purchase.  If clean feed is unavailable or prohibitively expensive to access, isolate the feed and livestock being fed to a confined area in order to isolate weed seeds that will be excreted in their manure.  This is to facilitate the monitoring and eradication of any new weed introductions, before they spread and become a production concern.
7. Do spot spraying.
8. Remove initial infestations while still small, either by hand or with herbicides.
9. Maintain a uniformly competitive grass cover to prevent and/or reduce an infestation in pastures, roadsides and non-crop areas.
10. Prevent seed set/formation by mowing/swathing before flowering.
11. Harvest and till weed-infested areas separately.
12. For shallow rooted plants, rogue infested areas and put plants in a garbage bag to dispose of through burning or deep burial.
13. If the weeds are cut while in flower, bale up the weeds. The bales can later be destroyed by burning.
14. Consult the provincial Guide to Crop Protection for herbicide control. Read and follow label directions carefully. Use licensed applicators where required.
15. Keep a sense of humour.

Acknowledgements

Edited and revised in 2007 by Clark Brenzil, PAg, Provincial Weed Control Specialist, Saskatchewan Agriculture and Food, Regina.

This information was originally compiled and edited by Mona Lee Kirkland, a former Rangeland Agrologist with the Grazing and Pasture Technology Program.

References and Suggested Readings

Anonymous, 1990. Managing Saskatchewan Rangelands - New Pastures and Grazing Technologies Project.

Best, K.F., Bowes, G.G., Thomas, A.G. and Maw, M.G. 1980. The Biology of Canadian Weeds. 39 Euphorbia esula L. Can. J. Plant Sci. 60:651-663.

Budd, A.C. 1957. Wild Plants of the Canadian Prairies. Experimental Farms Service. Canada Department of Agriculture. Publication 983.

Canadian Gardening. February/March. 1995. 29-31.

Crop Protection Section. 1984. Weed Control Notes. Saskatchewan Agriculture and Food.

Hutchens, A.R. 1991. Indian Herbalogy of North America. Shambhala Publications Inc.

Johnson, E. and Klein, L. Yellow Toadflax Biology and Control. District 30 Agriculture, Development and Diversification Board.

Kessler, D. Scentless Chamomile: Distribution. Agriculture Canada.

Kessler, D. Scentless Chamomile: Seed Production and Germination. Agriculture Canada.

Kessler, D. Scentless Chamomile: Habitats. Agriculture Canada.

Kessler, D. Scentless Chamomile: Identification. Agriculture Canada.

Looman, J. 1983. 111 range and forage plants of the Canadian prairies. Agriculture Canada, Research Branch. Publication 1751.

Looman, J. 1982. Prairie grasses - identified and described by vegetative characters. Agriculture Canada, Research Branch. Publication 1413.

Looman, J. and Best, K.F. 1979. Budd's Flora of the Canadian Prairie Provinces. Agriculture Canada, Research Branch. Publication 1662.

Maw, M.G., Thomas, A.G. and Stahevitch, A. 1985. The biology of Canadian Weeds. 66. Artemisia absinthium L. Can. J, Plant Sci. 65:389-400 (Apr. 1985).

Mitich, L.W. 1993. Yellow Toadflax, Weed Technology. 1993. 7:791-793.

Mitich, L.W. 1979. Weeds Today/Winter, 1979.10(1):21.

Mitich, L.W. 1992. Tansy. Weed Technology. 1992. 6:242-244.

Moss, E.H. 1977. Flora of Alberta, University of Toronto Press.

Mulligan, G.A. 1989. Common Weeds of Canada - Field Guide. NC Press Limited.

Saner, A., Clements, D.R. Hall, M.R. Doohan, D.J. and Crompton, C.W. 1994. The Biology of Canadian Weeds. 105. Linaria vulgaris Mill. Can. J. Plant Sci. 75:525-537.

Spellenberg, R. 1994. National Audubon Society - Field Guide to North American Wildflowers - Western Region.

Stearman, W.A. and Wheeler, G. 1985. Weeds of Alberta. Alberta Environmental Centre and Alberta Agriculture.

Stubbendieck, J., Hatch, S.L. and Hirsch, K.J. 1986. North American Range Plants. Third Edition. University of Nebraska Press.

Stubbendieck, J., Nichols, J.T. and Butterfield, C.H. 1989. Nebraska Range and Pasture Forbs and Shrubs. Nebraska Co-operative Extension E.C. 89-118.

Vance, F.R., Jowsey, J.R. and McLean J.S. 1989. Wildflowers Across the Prairies. Western Producer Prairie Books, Saskatoon, Saskatchewan.