Managing Biologicals

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Managing Biologicals

• Ent 547
• Fundamentals of Biological Control
• Fall 2005

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• Managing Biologicals and Integrated Pest
  Management (IPM)
• Are they the same?
• Most definitions of IPM have the basic idea of
  managing pests through an understanding of their
  interactions with other organisms and the
  environment.
• Is this really the case?

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Our Definition of Biological Control With Microbes

• Pest suppression with biological agents operating
  in a background of integrated control that does
  not depend on host resistance, sterilization of
  the target pathogen, or modification of pest
  behavior

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Four Elements of IPM

• Manage resources
• Cropping system, functioning ecosystem where
  actions are taken to restore a balance and not
  eliminate species.
• Risk or damage assessment before action.
• Consider all and use best management options.
• Integrate a combination of techniques in a
  compatible manner.

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Ecological Context of IPM

• Integrated Pest Management?
• Integrated Pesticide Management?
• Improved Pesticide Marketing?
• Whats usually missing is the ecological based
  context of IPM
• Why is the pest (pathogen) there?
• How did it arrive?
• Why doesnt the parasites and predators control
  the pest?

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Relative Management Practices
Chemical Control
Applied Biologicals
Reactive
Mechanical and Physical Controls
Monitoring, ID of Pests and Beneficials
Monitoring, ID of Pests and Beneficials
Sanitation, Plant Dates, Crop Rotation
Above ground beneficial habitat and healthy soil
Crop genetic diversity, ecosystem and pest
appropriate cultivars
Proactive
Low
High
IPM Process/Input
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The IPM Manager

• Ecosystem Manager
• Plan before cropping
• Agricultural ecosystem design
• Habitat
• Crop rotations
• Choice of resistant cultivars
• Collect technical information
• Develop monitoring, record keeping, sampling
  equipment procedures
• Know the biology of the pest and beneficials

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Proactive Strategies

• Farmscaping is a whole-farm ecological approach
  that uses plants, water reservoirs, etc. to
  support beneficial organisms
• Goal is to increase diversity and may be
  dependent on organic matter, pH, nutrient
  balance, moisture, soil type, micro and
  macroflora.

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Proactive Strategies

• Crop genetic diversity may lead to lower
  incidence of disease
• Multiple resistance cultivars
• Intercropping the practice of growing two or
  more crops in the same, alternate, or paired rows
  in the same area.
• Crop rotation
• Interplanting seeding or planting a crop into a
  growing stand.

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PolyFace Farms, Inc. Virginia Joel
Salatin http//www.polyfacefarms.com/
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Microbial Pathogen Management

• Conservation preserving or enhancing conditions
  for microbial competitors, parasite survival
• Augmentation increase agent populations by mass
  rearing and addition to the crop

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Conservation

• Root Diseases?
• Foliar Diseases?
• Plant-Parasitic Nematodes?

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Augmentation

• Root Diseases?
• Stem Diseases?
• Foliar Diseases?
• Leaf
• Flower
• Fruit

See E. Fred Legnere. Biological Control of
Plant Pathogens. http//www.faculty.ucr.edu/legn
eref/biotact/bc-41.htmMethods_For_Biocontrol_of_P
lant_Pathog
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Example bioassay for biological control of a
plant pathogen. Begonias were grown in the
greenhouse and inoculated with Botrytis cinerea
under conditions optimal for the development of
disease. Treatments differing in their efficacy
are shown, from left to right untreated (Un),
CaCl2, chlorothalonil (Fung), and the biocontrol
agent Trichoderma hamatum T382 inoculated into
the potting mix (T382). Photo courtesy of Dr. H.
Hoitink.From http//www.apsnet.org/online/featur
e/biocontrol/top.html
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Induced Resistance, Hypovirulence

• Root Diseases?
• Foliar Diseases?

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r- and K-strategists

• r-strategists.
• High reproductive capacity.
• Dispersed.
• Establish readily in disturbed habitats.
• Establish readily where noncolonized resources
  are present.
• K-strategists.
• Dominant species as community matures and becomes
  more crowded.

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Agricultural Practices

• Agricultural practices include
• Method of tillage
• Planting date
• Plant spacing
• Choice of crop sequence
• Kind and placement of fertilizer
• Irrigation timing and intensity
• There is a potential to create many different
  niches by varying these practices.

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Agricultural Practices

• Potential Results
• Create niche(s) for antagonists
• Elimination of the pathogen
• Enhance of plant resistance
• Until the development of commercial microbial
  products, most efforts to enhance biological
  control focused in cultural practices, plant
  breeding, or both

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From http//www.apsnet.org/online/feature/biocont
rol/top.html
General Model for IPM Program including
biologicals
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What are the first steps in microbial control of
plant pathogens? Is special training
required? How do we manage plant diseases from an
ecosystem approach?

• Cropping Systems
• Cultivar rotation
• Crop rotation
• Monoculture crops
• Mixed or intercrop species

• Soil Treatments
• Tillage
• Crop residue management
• Organic amendments
• Flooding
• Solarization
• Soil fertility and nutrition management

• Irrigation
• Dryland
• Flooding
• Sprinkler
• Drip

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General Guidelines

• A major challenge for research on biological
  control achieved with agricultural practices is
  how to identify the best combination of practices
  to either
• Restrict the pathogens niche by making the
  environment less favorable for the pathogen than
  the host, antagonists, or both.
• Prevent development of a pathogens niche

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Guidelines

• Verify that plant in a field has less disease.
• Choose two fields that have the greatest
  difference in disease severity, incidence.
• Identify the most likely cultural practice
  responsible for the difference.
• Verify in other disease-free, or reduced disease
  level fields that the same or similar cultural
  practice has the same effect.