Kootenai County Seal, Administration Building, and Lake
  

Weed Specialists
Email: kcnoxiousweeds@kcgov.us
P: (208) 446-1290
F: (208) 446-1282

Physical Address:
Click here for map.
10905 N. Ramsey Road
Hayden, ID 83835

Office Hours:
Mon - Fri 8:00a.m. - 4:30p.m.

BIOLOGICAL CONTROL FOR WEED MANAGEMENT


Most successful weed management plans use a number of methods: herbicides, mechanical, cultural, and when appropriate biological control. Use of multiple methods at the same time is called Integrated Pest Management - or IPM.

Biological control of weeds is 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 permanently reduce the populations of selected weeds. They are used to REDUCE, not GET RID OF the weeds.


BIOLOGICAL CONTROL MAY BE AN OPTION FOR YOUR WEED PROBLEM IF.....
  • You don't expect the weed to be totally eradicated
  • You don't need instant gratification
  • You are willing to check release sites for establishment and impact
  • You are willing to give the agents the time they need to work (2-5+ years) before resorting to other weed management options (spray, mechanical,cultural)

Download a PDF
Biological Controls for Spotted Knapweed (139.11 KB)
Information on the biological controls working on spotted knapweed infestations.
Biological Control for Toadflaxes (157.02 KB)
Information on the biological controls working on controlling toadflaxes.
Biological Control of Weeds (295.11 KB)
Information on whether or not biological control of weeds will work for you.

SPOTTED KNAPWEED

Knapweed Agents - Thirteen insects have been released
that will attack knapweed species. Some prefer other
knapweed species over spotted. The most effective
established agents prefering spotted knapweed are
A.zoegana, C. achates, Larinus spp., and Urophora
spp. Work in Canada shows the best control if seedhead
feeders and root feeders are combined.


TOADFLAXES

Flower feeding beetles (Brachypterolus pulicarius)
are likely already in your yellow toadflax. A stem-boring
weevil (Mecinus janthinus) that attacks Dalmatian
toadflax is showing promise.


LEAFY SPURGE

Beetles (Aphthona spp.) that eat the leaves and seed
have been the most visible and effective so far. Grazing
by sheep, goats, llamas or hogs is an effective way to
keep the plants from blooming.


For a complete list of weeds and their biocontrol agents, visit http://www.nezpercebiocontrol.com/


Biological control agents - Click for identification
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aphthona_spp_adult2jpg.jpg cypho2.jpg dalmatian_toadflax_flower.jpg goats.jpg larinus_minutus.gif leafy_spurge_flower.jpg mecinus_adult_emerging.jpg sheep.jpg spotted_knapweed_flower_3.jpg uv_knapweed_seedhead_fly_2_urophora_quadrifas.jpg

FOR MORE INFORMATION:

USING LIVESTOCK FOR WEED MANAGEMENT

Prescription grazing - is carefully controlled grazing
to meet land management objectives. It can reduce weeds
in crop systems, control weeds in tree crops, remove
weeds in sensitive areas, and control weeds on range
lands.


KEYS TO PRESCRIPTION GRAZING
-Timing of grazing - when weeds are most susceptible and taste the best to the animal, generally early spring in North Idaho.
-Frequency of grazing - Depends on the weed species; life span, reproduction, longevity of seeds in the soil, and how it reacts to grazing.
-Stocking rate - How many animals do you need on how much acreage? It depends on the density of the weed infestation, the palatability of the weed, and your specific goals.

Pick the right animal for the job - Pick the correct species and breed for your weed. It is a myth that any old goat (or sheep, or cow) will do.

Website with grazing guidelines for weed control: http://www.webpages.uidaho.edu/rx-grazing/