Residents asked to be on the lookout for noxious weeds

Residents asked to be on the lookout for noxious weeds

Residents asked to be on the lookout for noxious weeds

Commissioners and residents of Lander County heard a noxious weeds informative update at the courthouse in Austin from Noxious Weeds Coordinator Sean Gephart of the Nevada Department of Agriculture.

A noxious weed, according to NRS 555.005 is “Any species of plant which is, or is likely to be, a public nuisance, detrimental or destructive and difficult to control.” Gephart said the difference between an invasive species like cheatgrass and a noxious weed is that noxious weeds are those specifically put on the state statute that need control. Gephart stated, “We have to be realistic that some of those weeds that are invasive that are not on the list are so widespread, we can’t do anything about it. Cheatgrass is not a noxious weed because it is so widespread that we can’t expect any level of control.”  

In response to the often-asked question, “Why are they considered noxious weeds when they’re so pretty?” Gephart said, “If you look at the federal list – about 1,000 or so – about 80% of those were brought into the horticultural industry, so they were pretty at one time but they just naturalized and escaped, and became a problem.”

The Nevada Department of Agriculture has the authority to designate noxious weeds to be put on the list and Gephart recently added seven new species, three specific to Northern Nevada. In order to add weeds to the list, the NDA develops a weed committee and looks at weed lists of neighboring states to see if they are encroaching. There are currently 54 species of weeds listed as noxious, and they are broken down into three categories: Those that are of limited distribution, those established in certain areas, and those that are widespread throughout the state. 

According to state law NRS 555.150: “Every person owning, controlling or occupying lands in the state and every county shall control all weeds declared noxious,” and Gephart said “Pinpoint the word ‘control’ – it doesn’t say ‘eradication.’ Yes, we would like to see eradication but we have to be realistic that some weeds are so widespread that just suppressing them from further development is really helpful.”  

Hoary cress is by far the most prolific noxious weed in Lander County. Gephart explained, “Hoary cress is a perennial, spread by roots and seeds, it grows best in disturbed alkaline soils, and frequent mowing for several years can reduce the plant density; however, if you rototill it, because the roots are propagative, you actually will make the problem worse. So, the last thing you want to do is rototill a patch of hoary cress.” Gephart suggested mowing it or spraying it with the common herbicide 2,4-D before it goes to seed. Other noxious weeds infesting Lander County are Scotch thistle, Canada thistle, poison hemlock, perennial pepperweed, musk thistle, Russian knapweed, salt cedar, yellow starthistle, spotted knapweed and diffuse knapweed.

Russian knapweed, a perennial with a creeping root system and dormant seed germination, is toxic to horses and causes starvation and dehydration due to Chewing Disease. 

Russian knapweed is heavily infesting the area, and Gephart illustrated some of the USDA-tested biological control agents he uses, such as the gall wasp or gall midge. Control agents can be insects, fungi and bacteria that restrict further growth, and they are host-specific and do not damage other plant life. Gephart explained the gall wasp is very small, the size of the head of a pin, and it lays its eggs in the top portion of the Russian knapweed plant just below the flower, and as the eggs get larger the plant develops a gall, preventing the plant from going to seed. 

Gephart said if he could walk away with one weed that he wanted everyone to be familiar with, it would be the yellow starthistle, “because it’s marching this way. It’s heavily infesting Washoe County, and it is one of the major contributors to California wildfires, as once it dries, it produces a great deal of dead matter.” Yellow starthistle is an annual weed and treating it before it goes to seed is important.

A new noxious weed of concern for Lander County is Ventenata dubia or wiregrass, a winter annual grass that germinates in fall, with a shallow root system that may increase erosion. It is a noxious weed in Montana, is found in Elko, and is a problem in grass hay stands.

Gephart collaborates with state and county conservation districts and weed districts, and said, “We have crews that can do mapping and survey work for you,” and explained some available programs. 

Gephart said the Weed Free Gravel and Weed Free Hay Certification Program works by sending out an inspector to inspect either hay fields or gravel pits to determine if there are noxious weeds on site. “If we find that it’s clean, then we can certify it as weed free, and the benefit of that is the producer of gravel or hay can now sell that to people who want to use it on federal land or projects, or say a mule train or something like that.” That program is required for use when feeding horses and mules kept on federal lands, for use in fire restoration sites, for use in federal construction projects, and it increases the value of the product and limits the spread of noxious weeds.

Noxious weeds are detrimental to native plant species, wildlife habitat, agricultural yields, water quality and property values, and can cause an increase in rodent populations. Gephart said the public can report noxious weeds via cellphone or the NDA website at, and record the GPS location, a photo of the plant(s), the approximate size of the infestation and any additional data.