Diagnosing Disease and Insect Problems

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Diagnosing Disease and Insect Problems

• Debbie Miller
• Davey Tree Expert Company
• Kent, Ohio

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Types of Plant Problems

• Insect/Animal
• Disease
• Cultural
• Environmental
• Invasive species

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Disease Organisms

• Fungi
• Bacteria
• Viruses
• Phytoplasmas / Mycoplasmas

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Insect, Mites and Animals

• Sucking
• Chewing
• Boring

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Cultural

• Gas leak
• Chemical mis-application
• Irrigation

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Environmental Problems

• Temperature fluctuations
• Drought
• Flooding

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Importance of Diagnosis

• Identify the causal agent
• Implement corrective measures
• Chose most effective chemical
• Correct timing of application

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Plant History

• When plant transplanted
• Site information
• Soil type
• Light availability
• Past weather history
• Chemical history

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Winter Injury

• Symptoms first seen March through May
• Mistaken for disease or mite problem

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Bud Blast on Hemlock
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Winter Injury

• Spring frost injury on Callery pear
• Mistaken for deicing salt injury or fire blight

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Fire Blight Callery Pear
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Fire Blight Crabapple
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Fire Blight Management

• Plant resistant varieties
• Prune during late summer or during dormant season
• Increase air circulation
• Bactericides
• Aliette begin prebloom
• Streptomycin Start at blossom
• Repeat applications necessary

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Winter Injury on Alberta Spruce

• Needle browning
• Premature defoliation
• Aesthetic value

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Mite Injury

• Management
• Water
• Fertilize
• Miticides
• Hexagon
• Avid
• Horticultural oil

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Phomopsis Blight
Management

• Prune
• Water
• Fungicides
• Cleary's 3336
• Banner Maxx

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Deicing Salt Injury
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White Pine Sheath Mite

• Symptoms
• Needle browning
• South side
• Late March

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White Pine Sheath Mite
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Management

• Monitor trees on south side
• Send sample into Diagnostic Lab
• Application in late winter/early spring
• Horticultural oil
• Avid, Sevin
• Late summer/early fall application

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Balsam Twig Aphid
Canadian hemlock
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Balsam Twig Aphid
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Balsam Twig Aphid
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Management

• Heavy population water and fertilize
• Monitor needle undersides for pale greenish
  insects feeding alone in April

• Tap branch over black embroidery hoop
• Apply horticultural oil in early spring before
  bud break
• Dormant oil does not manage overwintering eggs.

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Sycamore Anthracnose
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Management of Sycamore Anthracnose

• Trunk injection with Arbotect (2-yr preventative
  protection)
• Foliar application of broad spectrum fungicide
  Clearys 3336 at bud break
• Thin canopy
• Plant resistant plants, i.e. London Planetree

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Bagworms on Conifers
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Bagworms - Crabapple
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Bagworms Honeylocust
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Bagworm Management

• Pick off bagworms
• Early instars - Bacillus thuringiensis (B.t.)
• i.e. Dipel, Foray
• Later instars
• Conserve, Talstar, Sevin, Orthene

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Viburnum Leaf Beetle
Overwinters as eggs
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Viburnum Leaf Beetle

• Larvae skeletonize and chew leaves in May

Adults feed July to September
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Viburnum Leaf Beetle Management

• Avoid highly susceptible species
• European cranberrybush, arrowwood and Sargent
  viburnum
• Plant resistant species
• Viburnum burkwoodii, V. carlesii
• Merit soil injections in fall or spring
• Foliar insecticide applications of Talstar,
  Sevin, Orthene
• Water and fertilize

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Gypsy Moth
Overwintering egg mass and gypsy moth adult
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Gypsy Moth Defoliation
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Gypsy Moth

• Management
• Aerial sprays by government agencies
• Trunk protection
• Foliar spray
• 1st 2nd instar - B.t.
• 3rd instar Conserve
• Water fertilize

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Oak Wilt
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Oak Wilt
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Sample Collection
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Oak Wilt Management

• Water and mulch to prevent drought
• Red oak family
• Removal
• White oak family
• Treat if less than 2 crown loss
• Alamo trunk injection in summer
• Root trench
• Remove bark for firewood
• Avoid pruning between April and October

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Lecanium Scale
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Calico Scale
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Scale Management

• Apply a Merit soil drench in April
• Post water for maximum uptake
• In 6 weeks follow-up with Safari foliar
  application
• Prune out dead twigs
• Water and fertilize

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Rose Rosette
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Rose Rosette

• Causal agent
• Uncertain eriophyid mite or virus
• Management
• Treat for eriophyid mites Avid or Sevin at bud
  break
• Prune out affected branches
• Sterilize pruning tools
• Eliminate multi-flora rose close to other roses.

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Hypoxylon Canker
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Hypoxylon Canker
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Hypoxylon Canker
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Resistograph

• Compares amount of sound wood to decayed wood
• Hazard tree determination

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Lace Bugs
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Lace Bug Management

• Monitor for pest or injury
• Merit soil drench
• Insecticide applications
• Good coverage on leaves and undersides
• Multiple generations multiple applications
• Water and fertilize

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Zimmerman Pine Moth
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Zimmerman Pine Moth

• Pitch masses at branch whorls
• Sap has reddish frass
• Management
• Remove brood tree
• Treat trunk and branch whorls with Astro in April
  again in September
• Water and fertilize

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Submitting a Sample
Bad sample
Ganoderma
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Customers Dancing for Joy
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• Debbie Miller
• Davey Tree Expert Company
• Kent, Ohio
• 330-673-9511

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The End