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Spotted Knapweed in Montana

Spotted Knapweed in Montana. Ecology. http://www.greenfield-industries.com/Noxious.shtml. Spread of Knapweed. 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.

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Spotted Knapweed in Montana

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  1. Spotted Knapweed in Montana Ecology http://www.greenfield-industries.com/Noxious.shtml

  2. Spread of Knapweed • 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

  3. Knapweed Facts • 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

  4. Why is knapweed so successful? • 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_4fb461967c.jpg

  5. Why is Knapweed not a good replacement for native vegetation? • 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

  6. Response to knapweed problem: • 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.

  7. Bio-Control • 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

  8. Why is it important to research bio-controls before introducing them in the US? • What if the bio-controls attack wheat or native plants here?

  9. Biological Control Agents • 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/3617/3651122688_23b73dba61.jpg

  10. Biological Control Agents • Yellow Root Moth • Larinus (beetle) • Root Weevil • Feeds off the weeds root http://www.idahoag.us/Categories/PlantsInsects/NoxiousWeeds/Images/Bio_Control/Agapeta_zoegana.JPG http://www.invasive.org/images/768x512/0886054.jpg

  11. Why might biological control be better than using chemicals? • More effective • Affordable • Safer

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