2. Weed Biological Control Principles and Procedures J. P. CUDA ENTOMOLOGY & NEMATOLOGY DEPARTMENT GAINESVILLE, FL 32611-0620

3. Instructor: Dr. Jim Cuda phone (352-392-1901 ext 126) email (jcuda@mail.ifas.ufl.edu) Instructor: Dr. Jim Cuda phone (352-392-1901 ext 126) email (jcuda@mail.ifas.ufl.edu) Research Area: Biological Control of Aquatic & Terrestrial Weeds Research Area: Biological Control of Aquatic & Terrestrial Weeds

4. Topics Weed Biological Control ConceptsWeed Biological Control Concepts Steps in a Classical Biological Control ProgramSteps in a Classical Biological Control Program

5. What is a Weed ? A plant out of place (HOLM ET AL. 1977)A plant out of place (HOLM ET AL. 1977) Introduced or native plant growing in a situation where it has a detrimental effect on conservation areas, humans, or their environment (HARLEY & FORNO 1992)Introduced or native plant growing in a situation where it has a detrimental effect on conservation areas, humans, or their environment (HARLEY & FORNO 1992)

6. Strategies Used For Weed Management Control Method MechanicalMechanical ChemicalChemical BiologicalBiological Infestation Infestation SmallSmall ModerateModerate WidespreadWidespread

7. Criteria for Selecting a Weed as a Target for Biological Control Cause sufficient damageCause sufficient damage –Agricultural –Ecological No critical beneficial valuesNo critical beneficial values Existence of natural enemiesExistence of natural enemies

8. What is Biological Control ? Use of live natural enemies to suppress weed densities or populationsUse of live natural enemies to suppress weed densities or populations Examples of natural enemies :Examples of natural enemies : –Pathogens (nematodes & diseases) –Arthropods (insects & mites) –Fish (grass carp)

9. Biological Control vs. Natural Regulation Biological Control vs. Natural Regulation “Biological Control” is an action taken by people“Biological Control” is an action taken by people “Natural Control or Regulation” has no human involvement“Natural Control or Regulation” has no human involvement

10. Biological Control Methods 1.Non-Classical Biological Control a.Augmentative Approach b.Inundative Approach 2.Classical Biological Control

11. 1. Non-Classical Biocontrol a.Augmentative - Mass rearing and release of a biological control agent to increase biological control agent to increase its numbers and effect on the weed its numbers and effect on the weed - Applies to fish (grass carp) and some insects (milfoil weevil )

12. 1. Non-Classical Biocontrol b.Inundative: - Formulation and application of - Formulation and application of pathogens to control weeds pathogens to control weeds - Applies to mycoherbicides Cercospora rodmani – Water Hyacinth Mycoleptodiscus terrestris - Hydrilla Mycoleptodiscus terrestris - Hydrilla

13. 2. Classical Biological Control Introduction of natural enemies from their native range to control an invasive exotic weedIntroduction of natural enemies from their native range to control an invasive exotic weed Most widely used methodMost widely used method

14. Ecological Basis for Classical BC Some natural enemies are host specific (WAPSHERE ET AL. 1984)Some natural enemies are host specific (WAPSHERE ET AL. 1984) In the absence of their own predators and diseases, densities of natural enemies are influenced by their host plant abundance (DEBACH 1974, HUFFAKER 1984)In the absence of their own predators and diseases, densities of natural enemies are influenced by their host plant abundance (DEBACH 1974, HUFFAKER 1984)

15. BIOLOGICAL CONTROL (= APPLIED ECOLOGY) 2o2o 1 o Consumer Producer (WEED) WEED 1 o Consumer (BIOAGENT) WEED

16. Objective of Biological Weed Control Introduce or apply natural enemies that can suppress and maintain the density of the weed at “ACCEPTABLE” levelsIntroduce or apply natural enemies that can suppress and maintain the density of the weed at “ACCEPTABLE” levels Biological Control is NOT eradicationBiological Control is NOT eradication

17. Conceptual Basis for Weed Biological Control Weed establishes equilibrium density (ED)* above economic injury level (EIL)**Weed establishes equilibrium density (ED)* above economic injury level (EIL)** Natural enemy lowers ED & maintains it below EILNatural enemy lowers ED & maintains it below EIL *ED - Long term mean density *ED - Long term mean density **EIL – Lowest density causing economic or ecological damage TIME NUMBER EIL ED Natural Enemy Weed

18. Defining Biocontrol Sucess Defining Biocontrol Sucess Complete- No other control methods are neededComplete- No other control methods are needed Substantial - Other methods needed but at reduced levelSubstantial - Other methods needed but at reduced level Negligible- Other methods are required (HOFFMANN 1998)Negligible- Other methods are required (HOFFMANN 1998)

19. Advantages of Biological Control Advantages of Biological Control Minimal impact on non-targetsMinimal impact on non-targets Environmentally friendlyEnvironmentally friendly Classical biocontrol is permanentClassical biocontrol is permanent Suitable for weeds of natural areasSuitable for weeds of natural areas Relatively inexpensiveRelatively inexpensive

20. Costs / Benefits of Classical Weed Biocontrol Programs (after Mentz 1987) Release of Bioagent Time Benefits (+$) Costs (-$) Research & Development Maintenance & Monitoring

21. Disadvantages of Biological Control Disadvantages of Biological Control Control is not immediate (5–10 years)Control is not immediate (5–10 years) Except for mycoherbicides, little interest in commercializationExcept for mycoherbicides, little interest in commercialization UnpredictableUnpredictable –Some natural enemies fail to establish –Some natural enemies are ineffective

22. Summary of Steps in a Classical Biological Control Program USDA-ARS

23. Procedure for Classical Weed Biological control Procedure for Classical Weed Biological control 1.Project Initiation 2.Seek Approval and Funding 3.Foreign Exploration 4.Domestic Surveys 5.Ecological Studies on Weeds & Agents

24. Procedure for Classical Weed Biocontrol (CONT’D) Procedure for Classical Weed Biocontrol (CONT’D) 6. Host Specificity Studies 6. Host Specificity Studies 7. Seek Approval for Release of Agents 7. Seek Approval for Release of Agents 8. Rearing and Release 8. Rearing and Release 9. Evaluation of Effects 9. Evaluation of Effects 10. Distribution (& Augmentation)

25. Project Initiation Project Initiation Determine Plant is Suitable TargetDetermine Plant is Suitable Target –Conduct Literature Review on Weed and its Natural Enemies Taxonomy, Biology, Ecology, DistributionTaxonomy, Biology, Ecology, Distribution –Demonstrate Economic / Scientific Feasibility and Resolve Conflicts

26. Seek Approval and Funding Seek Political Support from StakeholdersSeek Political Support from Stakeholders –Cattlemen’s Associations –Water Management Districts Obtain Financial Support from Public and Private SectorsObtain Financial Support from Public and Private Sectors

27. Foreign Exploration Foreign Exploration Identify Native Range of Target WeedIdentify Native Range of Target Weed Search for Natural Enemies in Native RangeSearch for Natural Enemies in Native Range

28. Domestic Surveys Domestic Surveys Conduct Faunal Surveys of Weed in Introduced RangeConduct Faunal Surveys of Weed in Introduced Range Compile List of Arthropods and Pathogens Attacking Weed In Area of IntroductionCompile List of Arthropods and Pathogens Attacking Weed In Area of Introduction

29. Ecological Studies on Weed and Agents Ecological Studies on Weed and Agents Study Ecology of Weed and Its Relatives in Native RangeStudy Ecology of Weed and Its Relatives in Native Range Identify Natural Enemies and Study Their Biologies and Host RangesIdentify Natural Enemies and Study Their Biologies and Host Ranges

30. Host Specificity Studies Conduct Host Range Tests of Promising Natural Enemies in Country of OriginConduct Host Range Tests of Promising Natural Enemies in Country of Origin –Open Field Tests Preferable Study Host Specificity of Potential Control Agents in Quarantine in Country of IntroductionStudy Host Specificity of Potential Control Agents in Quarantine in Country of Introduction

31. Economic, Native and Endangered spp. Target Weed Other Plant Species; same subgenus Other Subgenera; same genus Other Genera; same tribe Plant Families of Economic/Aesthetic Value Plants Attacked by Relatives of Bioagents Redrawn from Rees et al. (1995) Centrifugal Phylogenetic Method (Wapshere 1974)

32. Screening Procedures (Wapshere 1989) Larval Feeding Test Adult Oviposition Test #1 Adult Oviposition Test #2 NOT IN HOST RANGE NOT IN HOST RANGE NOT IN HOST RANGE +- +- +- TEST 1 TEST 2 TEST 3 IN HOST RANGE No-Choice: Close Confinement Multiple Choice: Loose Confinement

33. Screening Procedures (cont’d) No Choice Tests No Choice Tests – Potted plants – Cut foliage

34. Screening Procedures (cont’d) Stem Cage Paired Test

35. Multiple Choice Tests Small Cages Large Cages

36. Seek Approval for Release Seek Approval for Release Prepare and Submit Report to Appropriate Regulatory Authorities Requesting Release of BioagentPrepare and Submit Report to Appropriate Regulatory Authorities Requesting Release of Bioagent Options:Options: –Release Approved –Additional Host Specificity Studies –Request for Release Denied

37. Rearing and Release Rearing and Release If Release of Bioagent is Approved by Regulatory Agencies:If Release of Bioagent is Approved by Regulatory Agencies: –Import Bioagent and Eliminate Parasitoids and Pathogens –Mass Rear and Release Bioagent

38. Evaluation of Effects Evaluation of Effects Confirm Establishment of BioagentConfirm Establishment of Bioagent Conduct Manipulative / Replicated Field Experiments to Measure Population Level Effect of Bioagent on Target and Non-Target SpeciesConduct Manipulative / Replicated Field Experiments to Measure Population Level Effect of Bioagent on Target and Non-Target Species

39. Distribution of Bioagent Distribution of Bioagent Redistribute Bioagent from Site of Establishment or Field InsectariesRedistribute Bioagent from Site of Establishment or Field Insectaries Collaborate with Public Agencies and Volunteer Groups to Spread Bioagent throughout infested areaCollaborate with Public Agencies and Volunteer Groups to Spread Bioagent throughout infested area

40. For Additional Information on Biologically Based Weed Management, Go To: For Additional Information on Biologically Based Weed Management, Go To: http://biocontrol.ifas.ufl.edu