Ecology

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 spread.jpg

 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

 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. b461967c.jpg

 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

 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.

 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

 What if the bio-controls attack wheat or native plants here?

 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 617/ _23b73dba61.jpg

 Yellow Root Moth  Larinus (beetle)  Root Weevil ◦ Feeds off the weeds root oxiousWeeds/Images/Bio_Control/Agapeta_zoegan a.JPG

 More effective  Affordable  Safer