Ornamental Integrated Pest Management (IPM) Notes

Ornamental Integrated Pest Management (IPM) Notes

Overview

• Date: 11/5/25
• Presenter: David Held, Professor and Chair of Landscape, Ornamental and Turf Production
• Contact Email: david.held@auburn.edu
• Reference Materials: Free downloadable book through library
  • Chapters Available:
  • Chapter 3: Plants in urban landscapes
  • Chapter 5: Sampling and Decision Making
  • Chapter 7: Woody Plant Pests

Ornamental Production

• High Fertility Requirement:
  • Plants require high levels of nutrients to thrive in ornamental settings.
• Outdoor Conditions:
  • The environment plays a critical role in plant growth and vulnerability to pests.
• Types of Plants:
  • Woody Plants:
    • Primarily those with at least 1 year in production.
  • Herbaceous Plants:
    • Typically have a shorter production cycle, generally under 1 year, sometimes between 1-2 months.
  • Modified Environment:
    • Indoor settings create a closed environment that impacts plant health.

Landscapes

• Definition:
  • Landscapes are considered contrived groups of plants with limited natural history.
• Impact of Diversity:
  • Increasing plant diversity influences pest abundance more significantly than increasing density.
  • Host Specialists:
    • Certain pests are specialized to particular host plants, impacting the ecological balance.

Damage Tolerance

• Comparative Tolerance:
  • Growers:
    • Generally have less tolerance for damage in ornamental production than consumers do.
  • Consumers:
    • They may be more accepting of aesthetic damage in landscape settings.

Pests and Pest Status

• Variability Influences:
  • Pest status may be influenced by a pest's ability to transmit pathogens.
  • A single species can show varying pest statuses in different situations.
  • An example includes the azalea, which may have a different range of pests based on circumstances.

Virus Transmission by Pests

• Methodology:
  • Certain pests, such as western flower thrips, can acquire and transmit viruses as adults.
• Notable Viruses:
  • Two significant viruses affecting ornamentals, both transmitted by thrips:
    • Impatiens necrotic spot virus
    • Tomato spotted wilt virus

Pests of Azaleas in Production

• Pest Categories and Status:
  

Pests of Azaleas in the Landscape

• Pest Categories and Status:
  

Thresholds for Ornamental Plants

• Yield Considerations:
  • Unlike agricultural landscapes, ornamental landscapes do not have yield measures.
• Perceptions of Damage:
  • Damage is assessed based on aesthetic perceptions, impacting treatment decisions.
  • There is no established EIL (Economic Injury Level) like in agriculture, but an AIL (Aesthetic Injury Level) exists.

Aesthetic Injury Levels (AIL)

• Injury Thresholds:
  • AIL is very low, with a threshold of about 5-6% injury being considered damaging.
  • This translates to approximately 4-9 bagworms per 4 ft tree (1-2 bagworms per ft of tree).

Conditional Thresholds

• Population Irrelevance:
  • Some species (e.g., stingers, biters, exotic species) show irrelevant population thresholds.
• Quarantine Treatments:
  • Quarantine treatments for species like fire ants may be necessary for outdoor production due to ecologically driven restrictions or regulations.
  • Exotic insects could have state or federal quarantines impacting pest management strategies.

Example of Influence on Potted Trees

• Referring to research by Frank and Ranger (2016):
  • Findings suggest a moisture content of 70-90% pre-disposes dogwood trees to borer attacks, potentially leading to tree death.
  • In contrast, no attacks were observed in trees that maintained 30-50% moisture levels.