Presentation on theme: "Noxious Weeds Carol Randall USDA Forest Service Forest Entomologist."— Presentation transcript:
Noxious Weeds Carol Randall USDA Forest Service Forest Entomologist
What is a Weed? “A plant out of place.” “A plant whose virtues have not yet been discovered.” “Plants obstructing the activities of man.” “A plant not valued for use or beauty, growing wild and rank, & regarded as cumbering the ground or hindering the growth of superior vegetation.”
Noxious vs. Obnoxious Weeds Noxious weeds are designated by a regulatory agency- and by law managers must manage these plants Obnoxious weeds are plants which can invade a site, but which are not considered enough of a threat to merit regulation
Why Manage Noxious Weeds? Noxious weeds have the potential to: Destroy wildlife habitat. Reduce recreation opportunities. Displace threatened and endangered species. Reduce plant and animal diversity. Disrupt waterfowl and migratory bird flight patterns and nesting habitats. Cost millions of dollars in treatment and loss of productivity to private land owners.
Have to be designated by law Director of the Idaho State Department of Agriculture makes legal designation for Idaho Idaho currently has 64 “noxious” weeds "Noxious weed" means any plant having the potential to cause injury to public health, crops, livestock, land or other property; and which is designated as noxious by the director. (Idaho Code 22-2402)
ISDA Criteria for Designating Noxious Weeds It must be present in but not native to Idaho It must be potentially more harmful than beneficial to Idaho Eradication must be economically and physically feasible The potential adverse impact of the weed must exceed the cost of control
Three Levels of Concern- Idaho’s Noxious Weed List Statewide Early Detection Rapid Response (EDRR) List Statewide Control List Statewide Containment List Brazilian Elodea, Giant Knotweed, Canada Thistle
Statewide Early Detection Rapid Response (EDRR) List Theoretically these plants are not well established in Idaho Focus is to identify populations of these weeds and eradicate them "Eradication" means the elimination of a noxious weed based on absence as determined by a visual inspection by the control authority during the current growing season European Frogbit Policeman’s Helmet
Something you probably did not know about Idaho… We are one of the most progressive states in the nation when it comes to addressing noxious weeds
Idaho’s Statewide Weed Education and Advocacy Groups Idaho Association of Weed Control Superintendents (IAWCS) Idaho Weed Coordinating Committee (IWCC) Idaho Weed Control Association (IWCA) Idaho Weed Awareness Campaign (IWAC)
Other Assets: Weed Science Program at the University of Idaho Research Programs at other State Institutes of Higher Education Cooperative Weed Management Areas
Cooperative Weed Management Areas (CWMA) Most of Idaho’s land mass is contained in one of 32 Cooperative Weed Management Areas (CWMA) CWMAs are formed when the landowners and land managers of a given area come together and agree to work cooperatively to control weeds CWMAs identify the highest priority weed control activities for their area, then share resources to get priority work done
So why is an entomologist talking about weeds? I work closely with county weed superintendents, CWMA’s, and weed researchers on classical weed biological control- or the use of insects to help control weeds
Idaho- A Biological Control of Weeds Super Power We have weed biological control researchers at our land grant college We have a statewide biological control coordinator (ISDA/BLM) We have designed and implemented the only statewide biological control of weeds monitoring program We have a number of statewide groups which cooperate on biological control of weed projects
How do you develop a weed treatment strategy Most successful weed management strategies incorporate a number of methods: herbicides, mechanical, cultural, and when appropriate biological control. Use of multiple methods simultaneously is called Integrated Pest Management- or IPM. A good weed treatment strategy relies on realistic management objectives, accurate weed identification and mapping, as well as post treatment monitoring. (“DID IT WORK?”)
Weed Biocontrol and other Control Methods Chemical Control - Picloram (Tordon) - 2,4-D - Glyphosate - Dicamba Cultural Control - grazing (sheep, goats) - hand-pulling, tilling - burning Biological Control - insects - pathogens IPM
What is Biological Control of Weeds? The use of one organism to control another. Classical Biological Control is the introduction of control agents- usually insects- into a region that is not part of their natural range, to suppress permanently the populations of selected target weeds usually also introduced into that region SUPPRESS not GET RID OF! Mostly geared towards containment list
How Biological Control Works Biocontrol agents may control weeds by destroying seeds, root, or stems; by weakening or stressing the weed; and/or by limiting the weeds ability to reproduce. Bioagent feeding may also help secondary pathogens infect weeds through damage scars. Once established and feeding in your weed infestations, biological control agents will continue to attack your weeds, month after month, year after year.
Lesser knapweed flower weevil Biocontrol population density Exponential increaseEstablishment of biocontrol agents Initial release Lagtime Larinus minutus
Biological Control Agent Outbreaks May Control Weed Infestations Beverly Bridge, AB Leafy Spurge Aphthona nigriscutis
Aphthona flea beetles for leafy spurge Biocontrol agents behave like insect pest species Mass outbreaks
Biological Control Basics: Uncertainty over ultimate scale of impact Long-term cost effective IrreversibleSelf dispersing (even into difficult terrain) Uncertain ‘non-target’ effects in ecosystems Gradual in effect, generally environmentally benign Protracted time until impact likely Continuous action Initial high costsTarget specificity DisadvantagesAdvantages
Things to Know: Efficiency of agents cannot be be be be be guaranteed. Will not work every time in every situation. Will not “eradicate” the weed. May not provide the desired level of control. Some times it might take awhile (years) before see biological control impact.