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.....
Thirteen insects have been released
that will attack knapweed species. Some prefer other
knapweed species over spotted. The most effective
established agents preferring spotted knapweed are
A.zoegana, C. achates, Larinus spp., and Urophora
spp. Work in Canada shows the best control if seed head
feeders and root feeders are combined. View the full list (PDF).
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. View the full list of agents (PDF) for weeds.
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.View the full list of agents (PDF).
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.
Learn more from the Targeted Grazing website with grazing guidelines for weed control.
Contact your State Department of Agriculture, County Noxious Weed Office, Local Cooperative Weed Management Area (CWMA) or Extension Agent.