Designated and Declared Noxious Weeds

The State of Wyoming has listed the following weeds as Designated Noxious Weeds. They are all non-native species and invasive in nature. Also included are two Declared Noxious Weed species in Fremont County.

Click on the picture or the name of the plant to see more information about that plant including control strategies.

Click Here To Report A Noxious Weed

CONTROL

The District directly controls designated weeds as funds and cooperative agreements permit. It encourages private landowners to control weeds on their own lands by cost sharing on pesticides and other proven control technologies. The cost share helps to reduce the economic impact of weeds on the property owner and guides control activities toward the most effective techniques.

Suppression of weeds in the core of the infestation helps reduce seed production and slows the spread of weeds. Yet, to be most effective, every new infestation needs to be eradicated as soon as it is found. Using the District's computerized mapping system coupled with continuous survey, we can identify those areas with few weeds and by controlling those few plants protect the surrounding area from infestation. If we charge the control cost to the acres treated, the cost per acre will look prohibitively high in comparison to boom spraying fields in the heart of the infestation, but if the cost is spread across the acres protected from invasion and compared to future treatment costs, it will look very reasonable.

Treatment of weeds on public road rights of way catch new infestations started when weed seeds fall off passing vehicles. Good weed control on irrigation rights of way protects neighboring lands and water users. Both irrigation ditches and gravel roads promote weed establishment and spread with constant disturbance related to maintenance. Fremont County Weed and Pest promotes good weed surveillance and control on public rights of way by entering into cooperative and contractual agreements with the managing entities for weed control services.

There are a number of control strategies. The foundation control strategy for invasive weed species is biological control where weed populations are beyond practical eradication. The next strategy is chemical control and then mechanical removal of small infestations in environmentally sensitive areas. These strategies are supported by improved cultural practices such as water control, competitive species, sanitation, and grazing management; all designed to strengthen the ecosystem against reinvasion.