Noxious & Invasive Weed Control


Noxious and invasive weeds are widespread throughout Nevada.  Noxious weeds have already invaded thousands of acres of Nevada’s lands and waterways and threaten water quality, wildlife habitat, recreational activities and the economic stability of ranchers, farmers and other land managers. 


A "noxious weed" is defined as any species of plant that is, or is likely to be, detrimental or destructive and difficult to control or eradicate (Nevada Revised Statute [NRS] 555.010-555.220). Noxious weeds and non-native invasive plant species have become a growing concern in Nevada.

Noxious weeds and non-native invasive plant species have the ability to readily establish and spread rapidly, particularly in disturbed areas.  They are spread by a variety of means, including: vehicles, construction equipment, construction and reclamation materials, livestock, wildlife and wind.  Vehicle traffic is a major contributor to weeds invading a new area because seeds and plant parts can become embedded in tire treads and any mud carried on a vehicle from an infested area.  Weeds often establish themselves along roadways.  Road maintenance activities, such as grading and adding gravel to roads, also is a means of spreading noxious weeds and non-native invasive plant species to roadside shoulders and ditches.  Animals also can spread seeds and plant parts that attach to their hair or fur and get caught in their hooves.


The spread of noxious weeds and non-native invasive plant species have resulted in substantial economic impacts on some sectors of Nevada.  As a result, the State has enacted laws requiring the control of noxious weed species (Nevada Revised Statutes - NRS 555, and Nevada Administrative Code - NAC 555).

In addition, the federal 
Noxious Weed Act of 1974, as amended (7 United States Code 2801 et. seq.) requires cooperation with state, local, and other federal agencies in the application and enforcement of all laws and regulations relating to the management and control of noxious weeds and non-native invasive plant species.

All noxious weeds are regulated by the 
Nevada Department of Agriculture.  CLICK HERE for an overview of Nevada's Noxious Weed Regulatory Program.


Noxious weeds are classified into three categories: A, B, and C.  Each category has specific control requirements, with the most stringent requirements for those species found in Category A.
Category A noxious weeds include weeds which are:
  • Generally not found or are  limited in distribution throughout the state; 
  • Actively excluded from the state and actively eradicated wherever found; and 
  • Controlled by the state for all infestations. 
Category B includes noxious weed species, which are:
  • Generally established in scattered populations in some counties of the state; 
  • Actively excluded where possible; and 
  • Controlled by the state in areas where populations are not well established or previously unknown to occur. 
Category C includes noxious weeds, which are:
  • Currently established and generally widespread in many counties of the state; and 
  • Controlled and abated at the discretion of the state quarantine officer (Nevada Department of Agriculture 2006).

For more information regarding a specific noxious weed species, visit the Nevada Department of Agriculture’s Nevada Noxious Weed webpage.

One noxious weed that is causing significant problems with water resources throughout Nevada is tamarisk (Tamarix spp.) also known as saltcedar. Tamarisk, an introduced species, is known for its enormous consumption of water. It is estimated that a single mature tamarisk plant can consume 200 to 300 gallons of water per day. In addition to monopolizing limited sources of water, tamarisk exudes salt from its leaves which changes the chemistry of the surrounding soil, making it difficult for understory plants to establish, compete, and survive (from: Joining Forces to Fight Tamarisk in Nevada).  

Nevada Department of Agriculture

University of Nevada, Reno