Biological Control

1
Biological Control

• Introduction and management of selected natural
  enemies of a weed.

2
BiocontrolWhen weeds run amok!

• Not the total solution but
• Economical
• Self-sustaining
• Environmentally safe

3
Downside

• New BCA introduction 1 in 3 in three chance of
  success.
• Slow process
• Efficacy is highly variable.
• Monitoring is required Just cant walk away

4
Successes

• St. Johnswort (Klamathweed) (Chrysolina Beetle)
• Tansy ragwort (Ragwort flea beetle)
• Rush skeletonweed. (Puccinia rust)

5
Emerging Successes

• Leafy spurge
• Diffuse knapweed
• Purple loosestrife
• Yellow starthistle.

6
BCA Impacts on Weeds

• Direct - destroys vital plant tissues and
  functions.
• Indirect - impact increases stress on the weeds,
  which may reduce their ability to compete with
  desirable plants.

7
Integrating Biocontrol

• Reduce weed populations
• Not eradication
• Competitive plantings may be used to compete the
  weeds.
• Part of the tool box

8
Biocontrol Programs are

• Not silver bullets
• Good for hard-to-treat sites
• Not for the impatient.

9
Biological Control Programs need

• Consistent Funding
• Expertise
• Cooperation

10
Biocontrol Advantages

• Reduction of herbicide residues in the
  environment,
• Host specificity on target weeds
• Long-term self-perpetuating control
• Low cost per acre
• Resistance management

11
Biocontrol - Disadvantages

• Limited availability native homelands
• Dependence of control on plant density
• Slow rate at which control occurs
• Biotype matching
• Difficulty of conflicts over control of the weed
• Host specificity when host populations are low.

12
Release Sites

• Large, contiguous infestations facilitates
  spread.
• Fit the ecological needs of the biocontrol
  agent
• Easy access but also protected and undisturbed.
• Minimum of 5 year project (preferably 10)
  years.
• Land owner agreements in writing
• Well marked, photographed and mapped

13
Biological control agents are living entities and
require specific conditions to survive.

• http//www.mtwow.org/Bio-Control-main.htm
• http//mtwow.org/leafy-spurge-biocontrol-links.htm
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• http//www.bio-control.com/products.asp
• http//www.extension.unr.edu/Weeds/Biolcontrol.htm
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