Working together to strengthen and support noxious weed management efforts in Montana.
This MontGuide describes oxeye daisy biological and ecological characteristics. It also provides mechanical, cultural and chemical management options to control this species.
Click to download load this publication for Montana State University Extension publications.
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.
Authors: Kim Goodwin, Roger Sheley, Robert Nowierski and Rodney Lym
Summary: Identification, life cycle, distribution, physical control, plant competition, grazing management, biological and chemical control, suggested management plan. 25 pages. 12 color photos, distribution map for U.S. and southern Canada, tables, graphs and appendix detailing habitat requirement, biology and collecting suggestions for currently approved insect biocontrol agents.
Click to download load this publication for Montana State University Extension publications.
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.
Montana State University Extension has published a great 12 page booklet with information that will allow you to identify the different Hawkweeds found in Montana.
This publication includes descriptions, photos showing the details of what to look for in the different lifestages of this plant.
It is free from MSU extension. Download a copy here today.
MontGuides are self-learning resource from Montana State University Extension.
“The hawkweeds are a very large genus of plants with approximately 25 species in North America. Hawkweeds are members of the sunflower family and are closely related to dandelion, chicory, prickly lettuce and sowthistle. Like some of their relatives, hawkweeds can rapidly colonize and dominate forest meadows, pastures and roadsides. In addition to reproducing by seeds, hawkweeds are capable of spreading by rhizomes, stolons and adventitious root buds. These methods of vegetative reproduction and a tolerance for sites with low productivity are probably responsible for the ability of these plants to quickly establish and dominate new areas. ”
Download the MontGuide including information on the origin, identification, impacts and information on management of the hawkweed.
Common tansy has a long history of medicinal use, but in Montana it has become a problem weed in pastures and along roadsides, fence lines and stream banks. Common tansy is a category 1 noxious weed on the Montana Statewide Noxious Weed List.
This self-learning resource from Montana State University Extension discusses the most recent techniques for managing common tansy. It is 4 pages long and ready to be printed or save on your computer in PDF format. Click here to get your copy today.
On January 20th, the Billings Gazette featured an article about the BLM removing Russian Olive trees.
The trees were introduced as a fast-growing, hardy tree good for creating shelter belts, habitat and food for wildlife. Russian Olive tree is indigenous to Europe and Asia.  It can quickly colonize in riparian areas and out compete native vegetation, interfere with natural plant succession and nutrient cycling. Read the full article about the Bureau of Land Managements efforts.
Montana State University provides a great collection of extension publications. Many of these are available online, and provide a great way to learn more about some of the noxious weeds in Montana.
Cheatgrass is being added to our Priority 3 List. Learn all about this invader in in a Montguide devoted to cheatgrass.
Celestine A. Duncan1, Weed Management Services and Mark J. Renz, New Mexico State University
Hoary cress (Cardaria sp.) is also known as whitetop or little whitetop. It is a deep-rooted, creeping perennial mustard that spreads by seed and vegetative root growth. There are three species including lens-podded hoary cress (C. chalapensis), heart-podded hoary cress (C. draba); and globe-podded hoary cress (C. pubescens). Hoary cress is well adapted to moist sites including sub-irrigated and irrigated pastures and hay-fields, rangeland, and disturbed sites such as roadsides, railways, and ditch banks. It can also invade cropland including small grain and alfalfa fields. Hoary cress may reduce crop yields, displace native plants, and reduce biodiversity, wildlife habitat, and forage production. The weed contains glucosinolates that can be toxic to cattle (McInnis et al. 1993). Hoary cress begins growth early in spring from a rhizomatous root system and flowers by April or early May. Seeds are produced about a month after flowering.