Are gall flies invasive?

Gall Ties (Urophora species) were introduced to control populations of the invasive spotted knapweed, Centaurea maculosa. This species of knapweed has spread throughout the western United States and can cause many problemson rangelands and in natural areas.

Why is the Canada thistle a threat?

Canada thistle spreads rapidly; its extensive root system and clonal nature allow it to form monocultures, altering community structure, outcompeting native species, and reducing biodiversity. It also can threaten rare and endemic species.

How is the Canada thistle invasive?

It is not very tolerant of shade. Once established, if conditions are suitable, Canada thistle can form dense stands that shade out and displace native plants, changing the plant community structure and species composition and reducing biodiversity. It spreads rapidly and is very difficult to remove.

What do gall flies eat?

gall fly, any of several different species of insects that cause swelling (galls) in the tissues of the plants they feed on. This group includes gall midges and certain fruit flies (order Diptera), gall wasps (order Hymenoptera), some aphids (order Homoptera), and certain species of moths (order Lepidoptera).

Why are goldenrod gall flies important?

The Goldenrod Gall Fly’s Role in the Ecosystem The goldenrod gall fly is an important food source for several other insects and multiple species of birds. There are two species of parasitoid wasps that specialize on goldenrod gall flies. One species of parasitoid wasp will lay its eggs in the goldenrod gall fly eggs.

What eats Canada thistle?

Sheep and goats eat the tender young thistles in the spring. Later in the year the plants can be treated with salt or molasses to encourage grazing and trampling. Kathy Voth has a small business teaching cows all over the West to eat weeds, including Canada thistle.

How do you control Canadian thistle?

Mid-May to mid-June (prior to flowering) — Herbicide treatments containing clopyralid, aminopyralid or glyphosate when the plant is in bud to flower stage can be effective for reduction of the population. Alternatively, mechanically cut Canada thistle prior to flowering with a rotary mower set at the highest height.

What are Canadian thistles good for?

A leaf tea made from Canada thistle is used as a tonic and diuretic and has been used for tuberculosis. Root tea is used to treat diarrhea (Foster & Duke 1990), and has emetic properties (Lewis & Elvin-Lewis 1977).

Where do gall flies lay their eggs?

The adult female wasps deposit eggs through the tender growing gall tissue into the interior chamber with a long ovipositor.

Where do gall flies live?

The Goldenrod Gall Fly is a parasite on goldenrod plants. The fly’s entire life, and death, is centered around Goldenrod. This small brown fly is about five millimeters long. Males are slightly smaller than females.

Is Canada goldenrod good for pollinators?

Goldenrod, on the other hand, is insect-pollinated. Its pollen sticks to the plant, where a happy host of bees and other insects have a feeding fest. In fact, some experts call it our single most valuable perennial plant for pollinators.

Does goldenrod attract bees or butterflies?

Attracting Pollinators with Goldenrods Goldenrod is an important fall pollinator plant. If you watch the golden plumes of goldenrods, you’ll see many tiny flies, bees, beetles, wasps, and butterflies moving through the blossoms. Goldenrod flowers are nectar rich. Bees are attracted to the nectar.

Should I pull Canadian thistle?

Organic Canada Thistle Control Find the base of the Canada thistle plant and simply snip it off at the base. Do not pull Canada thistle out, as this can split the root, which causes two Canada thistles to grow back.

How do I permanently get rid of thistle?

Use glyphosate for your garden, and use a broad-leaf herbicide containing 2,4-D or MCPP for your lawn. Since glyphosate kills all plants, you must keep application specific. Use a sponge to apply, or cut thistle plants and then use an eye-dropper to put a drop or two into the stem.

How do you stop Canada thistle from spreading?

How do I get rid of Canadian thistle?

Find the base of the Canada thistle plant and simply snip it off at the base. Do not pull Canada thistle out, as this can split the root, which causes two Canada thistles to grow back. Check the location weekly and snip off any new growth that you may see.

What is the best thistle Killer?

Several herbicides are effective and recommended for thistle control. Several newer herbicides like ForeFront, Milestone, and Chaparral are very effective. Two other very effective herbicides are Tordon 22K and Grazon.

Is Canada thistle poisonous to humans?

Toxicity. Canada thistle is not known to be toxic.

Do birds eat Canadian thistle?

Thistle seeds are a favorite with several seed-eating birds, like goldfinches. Seedlings require full sun for normal development.

What is the Canada thistle stem-gall fly?

The Canada thistle stem-gall fly is a biological control agent for use in controlling Canada thistle. In 2017 WCFA began facilitating the distribution of these agents to producers throughout the province, bringing them in from Montana. The stem-gall fly attacks the stem of the thistle plant, boring in and causing the plant to form gall tissue.

How do you get rid of gall flies in Canada thistle?

Planting competitive crops, such as alfalfa and forage grasses can be very effective in controlling an infestation of Canada thistle. Fly larvae of the stem gall fly Urophora cardui impact plant vigor in Canada thistle by inducing the plant to divert energy away from root and flower production to produce gall tissue in stems.

What causes Canada thistle gall to turn brown?

Larval—larvae mature inside of the stems of Canada thistle causing the plant to form a gall. When the plant dies or freezes, the gall becomes brown/gray and woody.

What is the difference between Canada thistle and Thistle?

Similar species: Canada thistle is distinguished from all other thistles by creeping lateral roots, dense clonal growth; and small dioecious flower heads (meaning male and female flowers are produced on separate plants). However, it is difficult to distinguish the two flower types based on appearance.