Biological Control and Vegetation Management

J.P. Cuda, Ph.D.Associate Professor

Entomology & Nematology DepartmentGainesville, FL 32611-0620

TopicsTopics•• IntroductionIntroduction•• Overview of Current ProjectsOverview of Current Projects•• Examine Potential ProjectsExamine Potential Projects•• Questions?Questions?

TopicsTopics•• IntroductionIntroduction

What is Biological Control ?• Planned Use of Undomesticated

Organisms to Reduce the Vigor, Reproductive Capacity, or Density of Weeds (DeLoach 1997).

• Four Categories:– Augmentation (Arthropods, Pathogens, Grass Carp)

– Conservation (Arthropods, Habitat Manipulation)

– Importation or Classical (Arthropods, Pathogens)

– Fortuitous (Arthropods, Pathogens)

TACTICS OF INTEGRATED WEED MANAGEMENTTACTICS OF INTEGRATED WEED MANAGEMENT

BIOLOGICALBIOLOGICAL CULTURALCULTURAL CHEMICALCHEMICAL MechanicalMechanicalPREVENTION

IMPORTATIONIMPORTATION AUGMENTATIONAUGMENTATION CONSERVATIONCONSERVATION INORGANICINORGANICORGANICORGANIC

NATURALNATURAL SYNTHESIZEDSYNTHESIZED NATURALNATURAL SYNTHESIZEDSYNTHESIZED

PERMANENT TEMPORARY

Relative Degree of Sustainability

FortuitousFortuitous

Importation (Classical) BioControl

•• Introduction of Introduction of Host SpecificHost SpecificNatural Enemies from the Natural Enemies from the WeedWeed’’s Native Range to s Native Range to Permanently Suppress the Permanently Suppress the Plant in its AdventivePlant in its Adventive11 RangeRange

11Arrived into a specified geographical region Arrived into a specified geographical region from elsewhere by ANY means.from elsewhere by ANY means.

Conceptual Basis for Classical BC• Native Host Specific Enemies Strongly

Control the Abundance and/or Distribution of Native Plants

• Escape from Host Specific Enemies is a Key Contributor to Exotic Plant Success

• Enemy Escape Benefits Exotics Because They Gain a Competitive Advantage Over Native Plants as a Result of Being Liberated from Their Pests

(Williams 1954)

Objective of Classical BioControl

• Introduce or Apply Natural Enemies to Suppress and Maintain the Density of the Weed at “ACCEPTABLE” Levels

• Biological Control is NOT Eradication

How Does BioControl Work ?

TIME

NU

MB

ER EIL

EDNatural Enemy

Weed

ED

• Weed establishes equilibrium density (ED)* above economic injury level (EIL)**

• Natural enemy lowers ED & maintains it below EIL

*ED - Long term mean density**EIL – Lowest density causing

economic or ecological damage

Advantages of Classical Weed BC

• Minimal Impact on Non-targets• Environmentally Friendly• Classical Biocontrol is Permanent• Suitable for Weeds of Natural

Areas– Minimal Disturbance

Disadvantages of Classical BC

• Control is Not Immediate (5–10 years)• Little Interest in Commercialization• Unpredictable

– Some Natural Enemies Fail to Establish– Some Natural Enemies are Ineffective

BioControl “Pipeline”

Credit: USDA, ARS

New Quarantine FacilitiesUSDA-ARS Laboratory, Ft. Lauderdale

UF/DACS Laboratory, Ft. Pierce

Defining BioControl Success(in Operational Terms)

• Complete- No other control methods are needed

• Substantial- Other methods needed but at reduced level

• Negligible- Other methods arerequired

(Hoffmann 1998)

TopicsTopics•• IntroductionIntroduction•• Overview of Current ProjectsOverview of Current Projects

(Habeck et al. 1989, Wheeler et al. 2001)

Brazilian Peppertree (BP)•• Fortuitous Fortuitous BioControlBioControl-- TorymidTorymid Seed Wasp Seed Wasp

Megastigmus transvaalensis

1.1. ThripsThrips-- Damages ShootsDamages Shoots

2. BP Sawfly2. BP Sawfly-- DefoliatorDefoliator

3.3. Seed WaspSeed Wasp-- Attacks FruitsAttacks Fruits

4. Weevil4. Weevil-- Stem/Root FeederStem/Root Feeder

5.5. PsyllidPsyllid-- Galls LeavesGalls Leaves

6. 6. LeafrollerLeafroller-- DefoliatorDefoliator

Brazilian Peppertree 11

22

33

55

66

44

Skunk Vine

Leaf Beetle Adult

Strawberry Guava

Data from Nguyen et al. (1992)

Tropical Soda Apple

Leaf Beetle Adult & Larva

Cogon Grass

Cogan Grass Infestation (left) and Treatment Plot with BioHerbicide

Melaleuca

Climbing Ferns

Adult Moth & Caterpillar

TopicsTopics•• IntroductionIntroduction•• Overview of Current ProjectsOverview of Current Projects•• Examine Potential ProjectsExamine Potential Projects

Purple Sesban, Rattlebox

Seed Weevil

J. Hoffmann, Capetown Univ.

Chinese Tallow

Leaf Beetle Adult

Plant Sucking Aphid

E. Siemann, Rice Univ.

Chinese Privet

Weevil Adult & Larva

For More BioControl Info:

http://http://ifasbooks.ufl.eduifasbooks.ufl.edu//

Brazilian Peppertree Management Plan

http://http://www.fleppc.org/Manage_Plans/schinus.pdfwww.fleppc.org/Manage_Plans/schinus.pdf

• 1st Edition of BP Management Plan

– 1997• Revised Management

Plan Completed– April 2006

• 2nd Edition Available– In Print and On-Line:

Traditional & Electronic Publications

http://edis.ifas.ufl.edu/index.html

Classical Biological Control of Weeds with Insects: Melaleuca Weevil1

J. P. Cuda, S.A. Wineriter, G.R. Buckingham, T.D. Center, and K.T. Gioeli2

http://http://plants.ifas.ufl.edu/guide/biocons.htmlplants.ifas.ufl.edu/guide/biocons.html

Web Sites

http://plants.ifas.ufl.edu/

http://ipm.ifas.ufl.edu/

TopicsTopics•• IntroductionIntroduction•• Overview of Current ProjectsOverview of Current Projects•• Examine Potential ProjectsExamine Potential Projects•• Questions?Questions?