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Ecology http://www.greenfield-industries.com/Noxious.shtml
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Weed used to only be present in Ravalli County (where we live). Today, it is found in all 56 counties Spread at a rate of 27.4% yearly since 1927 http://www.greenfield-industries.com/images/knap- spread.jpg
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The weed has spread across more than 4 million acres of Montana rangeland Effects of knapweed: ◦ Displaces food for livestock and wildlife ◦ Doubles soil erosion (makes it harder for native plants to grow and stay in the soil) ◦ Reduces land productivity by as much as 60% Means the land is no longer useful
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Chemical Warfare!!! ◦ Knapweed plants produce a substance that prevents native grasses from growing near it. ◦ The soil around the knapweed then becomes bare and erosion occurs. http://farm4.static.flickr.com/3207/2739693243_4f b461967c.jpg
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It only produces a few hundred pounds of ground cover per acre, compared to several thousand pounds produced by the grasses it replaced. Animals have less food to eat
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What can we do to decrease the amount of knapweed in Montana? ◦ Chemicals, manual removal, bio-controls Bio-control- Using naturally occurring organisms (like insects, fungi, etc.) to limit the distribution and abundance of weeds.
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Most of the weeds we have in the US are native to other areas in the world. ◦ In these other areas, there are natural predators of these weeds so the weeds are not much of a problem in areas they are native to. ◦ However, when these weeds came to the US, their natural predators did not come with them. ◦ After lots of research (usually 10 years), we can bring these predators to the US and turn them loose on the weeds
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What if the bio-controls attack wheat or native plants here?
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Gall Fly- ◦ The flies lay eggs in the buds of the knapweed plants, causing them to produce a gall, or cyst- like growth ◦ Growing the gall requires energy that the plant would normally use to produce seeds The plant ends up producing much fewer seeds http://farm4.static.flickr.com/3 617/3651122688_23b73dba61.jpg
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Yellow Root Moth Larinus (beetle) Root Weevil ◦ Feeds off the weeds root http://www.invasive.org/images/768x512/0886054.jpg http://www.idahoag.us/Categories/PlantsInsects/N oxiousWeeds/Images/Bio_Control/Agapeta_zoegan a.JPG
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More effective Affordable Safer
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