Plan to attend the next Nevada Weed Management Association (NWMA) conference. NWMA is hosting its 2015 conference, “Catalyst for Change: Opening the Conversation for Changing Nevada’s Noxious Weed Program”, in conjunction with a Medusahead Symposium, October 26-29, at the Nugget Hotel & Casino in Sparks, Nevada. More information regarding the symposium and conference can be found at NWMA’s website. Come be part of the discussion, learn about noxious weeds, weed management and engage in Nevada weed management issues. Presenters for these sessions have been invited from throughout Nevada, as well as several neighboring states. Breakout session that qualify will allow participants to earn continuing education units (CEUs) required for the renewal of applicator licenses, including a training on law.
EDDmapS map of Canada Thistle
Joy Paterson, Lyon County Extension Educator and UNCE–IPM team member, and Jamie Abbott, Noxious Weed Coordinator for Nevada Department of Agriculture (NDA) will be teaching a half-day workshop on EDDmapS including the website, data upload including how to upload data from other mapping software, map creation, smart-phone or tablet applications and other user features of the software. Tablets will be available to use during instruction, but participants are encouraged to bring their own laptops, tablets and smartphones. EDDmapS should be downloaded prior to the course. The course will include time for Joy or Jamie to assist with questions about your data or how to use the application or computer interface. Reporting noxious weed locations is important for use in demonstrating the extent of noxious weed issues in Nevada and using EDDmapS allows information to be shared nationwide.
Hope to see you there!
Musk Thistle Plant
Musk Thistle, Carduus nutans, is a biennial, noxious weed that occurs throughout the United States. EDDmaps reports it in Lyon county, where I took these photos. A rosette forms in the first year and the second year the plant will bolt and form a flower heads. The plant is solitary and does not spread vegetatively. The stems and leaves have spines. The flowers are white to pink or purple with spine tipped bracts at the covering the receptical, or base, of the flower. The flower heads often “nod” with the stem bending and the head tilting over to one side. Carduus species can hybridize, so morphological characteristics vary.
Musk Thistle Flower
Musk Thistle Rosette
Confirm your identification prior to treating an area. Native thistles can appear very similar to musk thistle, but pose no environmental or economic threat in agricultural, grazing or natural areas.
To control musk thistle, it is best to remove the plant in the first year, when it is a rosette and has not flowered. The tufted seeds spread easily with wind. Thistles only reproduces from seed, so mechanical control can be very effective. Mechanical control is most effective when the tap root is disturbed and destroyed. Once the plant goes to seed, the area will need to be monitored every year and any rosettes destroyed. Seeds readily germinate in disturbed soil, so plan mechanical controls in the spring prior to flowering from June to September.
Musk Thistle with “Nodding” Flower Heads
Biological control agents have been released for this weed in Nevada, but are no longer available for distribution and release. If you have a large contiguous patch, where other controls are not an option, you can monitor for the biological control agents by looking for the larvae in the root crown or seed heads. The spines and the detestable flavor of the plant prevent grazing by most animals, so control by grazing is not effective.
This time of year, the plants will have already gone to seed. If you notice the remainder of the plants, mark the location and plan to revisit the area in the spring to scout for rosettes. Prevention of further establishment is key to preventing this noxious weed from causing economic or environmental harm.
Joy Paterson assists Ray Johnson in releasing bindweed mites into a patch of bindweed
Never heard of bindweed? It is a vining plant with white and pink flowers. Field Bindweed has an expansive rhizome network underground where the plant can reestablish after mechanical or chemical treatments. The weed is not a common weed problem to have in Nevada, however, it is a common contaminant in seed and can cause economic loss and out-compete desirable vegetation once established. Ray and Virginia Johnson with Custom Gardens understand this all too well.
They contacted the University of Nevada Cooperative Extension to obtain information about biological control of bindweed. We directed them to our recent update of “Biological Control Options for Invasive Weeds in Nevada”. Ray and Virginia contact Nevada Department of Agriculture, who did not currently have a program for biological control of bindweed.
Ray with marked releases of bindweed mite
After contacting USDA-APHIS and obtained the necessary permits, they have received two species, a moth and a mite, with two releases of mites and one release of moths.
I was able to come out and help them with one of the mite releases. Ray and Virginia understand that biological control efforts require years if effort to control, so this is a fight that they will continue over the next few years. We are working together to find additional agent sources and I will stop back by this fall to check for establishment.