Biological Control
Biological control is the process of introducing a naturally occurring predator of a pest into the environment of which the pest has invaded. This is a key component in implementing an Integrated Pest Management (IPM) system for control of our declared and designated weeds and pests.
Leafy Spurge Beetles
At SCWP, we use flea beetles (Aphthona lacertosa and Aphthona nigriscutis) to help control leafy spurge infestations throughout the county. In late spring, the adults emerge and feed on the plant's leaf tissue. Almost immediately the females start laying eggs at the soil near the stem base. When the larva hatch, they begin feeding on the root system, severely weakening the spurge. This type of weed management is especially important in hard-to-reach areas where spray equipment is not feasible.
If you are interested in participating in this program, please contact us.
The image above is of a leafy spurge beetle of the species Aphthona nigriscutis
For our informational handout on the use of beetles click here
For more on our Leafy Spurge program click here
The image above is of a collection of leafy spurge beetles within a sweep net. While collecting, lots of other bugs get picked up and sorted out as well.
The image above is of a release of leafy spurge beetles of the species Apthona lacertosa
Mosquito Larvicide
As a part of our mosquito program all the major waterways in Sheridan County are sprayed with the organic larvicide Vectobac 12 AS. This is done typically 3 times each summer based on our monitoring of mosquito larvae populations. This larvicide is a naturally occurring soil bacteria that only attacks mosquito, blackfly, and fungus gnat larvae. The bacteria is Bacillus thuringiensis subsp. israelensis (Bti), which produce specific toxins that stunt the growth or kill the larvae of the aforementioned insects. For general sale of larvicide we also carry two different forms of this same bacteria.
This product will NOT affect, nor is harmful in any way to humans, honey bees, livestock, wildlife, fish or aquatic life.
The above image is of Big Horn Flying Companies airplane which is used to spray the mosquito larvicide. It is an Air Tractor 402.
For more info on our Mosquito program click here
Goat Grazing
Goats are small ruminants that have a big appetite for a wide variety of forage. They have a higher tolerance to toxic plants than other grazers making them ideal for targeted grazing management. Goats also destroy weed seeds as they pass through their digestive system. Sheep are a close second in effectiveness. Many of the weeds on our declared and designated weed lists are palatable to goats. Targeted grazing of these weeds is recommended in conjunction with other management methods for the best control.
This method is frequently used in our leafy spurge program. For this program we use a privately contracted goat herder to intensively graze 200+ goats on leafy spurge infestations.
For more information on targeted grazing please contact our office.
For more information on utilization of goats in our leafy spurge program click here
Shown above is the goat herd being moved onto target weeds by Jody Cheser
In this video a goat selects for leafy spurge while grazing
Up -and-Coming Biocontrols for our Programs
Tamarisk Beetles
Tamarisk beetles (Diorhabda spp.) are a natural predator of the invasive shrub salt cedar (Tamarix spp.). They defoliate the shrub as larva and adults which eventually kills the plant. They are very effective in control. Currently they are restricted from being moved across state lines but can be redistributed from active populations within the states borders. SCWPD is seeking out tamarisk beetle populations within Wyoming to be use on the salt cedar infestation along the Powder River.
If you have knowledge of current populations within Wyoming or historic release sites please let us know.
For more info on our salt cedar program click here
Russian Olive Moths
The larvae of Russian olive moths (Anarsia eleagnella) consume the seeds of Russian olive (Elaeagnus angustifolia) in their native region of Uzbekistan. Currently research is being done by CAB International to make sure release of these moths in the US would be a safe and effective strategy in reducing Russian olive seed spread. This would be very beneficial in reducing the spread of Russian olives across Sheridan county and decreasing the input of seeds into the environment. SCWPD is currently contributing to the funding of this research.
Canada Thistle Rust Fungus
Thistle rust (Puccinia punctiformis) is a fungal pathogen that has the ability to systematically infect and reduce Canada thistle populations over time. This rust fungus is host-specific and can only infest and survive on Canada thistle (Cirsium arvense L.). It is implemented as a biological treatment by spraying the inoculant on the leaves of invasive Canada thistle leaves in the Spring or Summer so that the fungus can be established and start to spread before it overwinters in the roots. The fungus got its name from the cycle of its spores turning a dark red rusty color as they mature on the bottoms of the thistle leaves. Canada thistle rust fungus is effective in reducing plant vigor as well as causing death. SCWPD is looking into providing this as a treatment option for Sheridan County land managers.