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Weed Calculator Available

Tuesday, June 15th, 2010

Have you ever wondered what the real impact is of weeds on your property?

Dr. Matthew Rinella has completed a project that will allow you in about 30 minutes with a pencil, clipboard, yardstick and a homemade measuring frame to figure out how weeds are impacting you. Dr. Rinella’s weed calculator will tell you how many pounds of weeds are on your property and if they were gone how much more good forage you would have.

This tool is great for ranchers and small acreage owners. If you are raising cattle, sheep, a few horses or like to watch elk graze you will find the results valuable.

The tool currently only will provide information on leafy spurge and spotted knapweed. Dr. Rinella hopes to expand this tool for use with other weeds. It is available free online.

Posts related to: Leafy Spurge, Spotted Knapweed
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Compatibility of Seed Head Biological Control Agents and Mowing for Management of Spotted Knapweed

Monday, April 5th, 2010

Authors: Jim M. Story, Janelle G. Corn, and Linda J. White

Summary: Seed head insects, primarily the seed head fly, Urophora affinis, and the seed head weevils, Larinus spp., are reducing spotted knapweed seed production by about 94% in most areas of western Montana. Studies were conducted on the compatibility of seed head biological control agents and mowing for management of spotted knapweed. Our study demonstrated that mowing of spotted knapweed in the spring and early summer can result in the growth of secondary flower buds which escape attack by seed head biocontrol agents, thereby allowing the knapweed to produce a nearly-normal complement of seed. Therefore, we conclude that the historical practice of mowing spotted knapweed during the spring and early summer with no follow-up mowings should be avoided if large populations of seed head biocontrol agents are present.

Download a copy of the research article.

Influence of Seed Head-Attacking Biological Control Agents on Spotted Knapweed

Wednesday, March 24th, 2010

Complete Title: Influence of Seed Head-attacking Biological Control Agents on Spotted Knapweed Reproductive Potential in Western Montana over a 30-year Period

Authors: Jim M. Story, Lincoln Smith, Janelle G. Corn & Linda J. White

Summary: Studies were conducted on the impact of seed head insects on spotted knapweed reproductive potential in western Montana over a 30-year period. Results indicated that seed head insects are reducing seed production by about 94% in many areas of western Montana. The reduction of knapweed seed production has resulted in a 98% reduction in the knapweed seed bank which, in turn, has contributed to the decline of knapweed in these areas. Of the seed head insects, the fly, Urophora affinis, and the weevils, Larinus obtusus and L. minutus, are having the greatest impact on knapweed seed production. The current decline of spotted knapweed in many areas is likely due to the impact of the seed head insects on the knapweed seed bank and the effects of the root weevil, Cyphocleonus achates, on mature plants.

Download a copy of the research article.

Decline of Spotted Knapweed Density in Montana with Large Populations of the Root Weevil

Monday, March 15th, 2010

Full Article Name: Decline of spotted knapweed density at two sites in western Montana with large populations of the introduced root weevil, Cyphocleonus achates (Fahraeus)

Authors: J.M. Story, N.W. Callan, J.G. Corn, L.J. White

Summary: Spotted knapweed plant density was monitored over a 11-year period (1993-2004) at two sites in western Montana where the root weevil, Cyphocleonus achates was released. Spotted knapweed density declined significantly over time at both sites (99% and 77%, respectively), after C. achates numbers increased dramatically at both sites. The current decline of spotted knapweed in many areas is likely due to the effects of C. achates on mature knapweed plants and the impact of the seed head insects on the knapweed seed bank.

Click here to download and read the complete article.

New Research Summary & Expertise Summary Published

Thursday, March 4th, 2010

Rocky Mountain Research Station Invasive Species Work Group publishes a new research summary and expertise directory.

In the first paragraph it states:

“Rocky Mountain Research Station (RMRS) personnel have scientific expertise in widely ranging disciplines and conduct multidisciplinary research on invasive species issues with emphasis in terrestrial and aquatic habitats throughout the Interior West, Great Plains, and related areas RMRS invasive species research covers an array of diverse ecological and environmental gradients, from southwestern deserts to northern temperate rain forests and from low-elevation plains and basins to alpine summits.”

The table of contents is as follows:

RMRS Invasive Species Research Program
Common themes of RMRS invasive species research
RMRS Invasive Species Research Priorities and Future Direction
Summary of Taxa-Specific Research
1. Plants
2. Pathogens
3. Insects
4. Aquatic Species
5. Terrestrial Vertebrates
Expertise Directory
Appendix

Download your personal copy of this great reference here.

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Transportation of Spotted Knapweed Seeds by Vehicles

Wednesday, January 27th, 2010

Vehicles have long been suspected of being a major distributor of spotted knapweed seed. The purpose of this experiment was to determine how many seeds could be disseminated by vehicles and to measure how far the seeds would travel. Sites were chosen at the Story Hills in Bozeman, the old Milwaukee Road rail yard in Deer Lodge and a site near the Bauxendale Volunteer Fire Department west of Helena. At each site, twelve plots each measuring twelve by forty feet were staked and the surrounding area was mowed. A late model pickup truck was driven 40 feet into each plot and backed out. The vehicle was then driven 25 mph for distances of 0, 0.1, 1.0, and 10.0 miles. The vehicle was placed on a large tarp and the entire undercarriage was vacuumed to collect spotted knapweed seeds and plant material. The collected material was bagged to await seed counting. At the Deer Lodge site, over 1633, 510, 226 and 138 seeds remained on the vehicle after traveling 0, 0.1, 1.0, and 10.0 miles. The results indicate that spotted knapweed seed is readily disseminated by motor vehicles for long distances.

Prepared by:

Phil Trunkle and Pete Fay
Department of Plant and Soil Science
Montana State University
Bozeman, Montana 59717

Download a PDF version of this document here.

Posts related to: Spotted Knapweed
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Effects of Sugar on Cheatgrass

Tuesday, January 15th, 2008

AN ABSTRACT OF THE THESIS OF
Jessi L. Brunson for the degree of Master of Science in Botany and Plant Pathology presented on January 15, 2008.
Title: Yield Responses of Invasive Grasses to Carbon Doses.

The sagebrush steppe ecosystem of the northern Great Basin is severely degraded and continues to decline due in large part to the invasive, non-native annual grasses Bromus tectorum L. (cheatgrass) and Taeniatherum caput-medusae (L.) Nevski (medusahead). Restoration of invasive-dominated areas is difficult, but can be enhanced by adding a carbon source, which stimulates microbes to immobilize soil inorganic N and reduces yields of fast-growing ruderal plants. How much carbon is needed to induce this effect is uncertain, so our research objectives were to establish a response to increasing carbon doses and calculate the lowest dose where a significant response was observed for 1) biomass, density, and seed production of cheatgrass and medusahead; 2) soil microbial biomass C and N; and 3) inorganic soil N. In November 2005 we applied 12 carbon doses ranging from 0 to 2400 kg C/ha as sucrose to plots planted with cheatgrass and medusahead at two sites in the northern Great Basin.

Read the complete article with the findings.

Posts related to: cheatgrass
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