Pests on Trees

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Pests on Trees

• Stephani Sandoval
• Extension Forest Health Specialist
• NMSU

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Outline

• Bark Beetle
• Disease
• Diagnosis
• Pesticides
• Prevention

• Pests
• Signs vs. Symptoms
• Deciduous Pests
• Conifer Pests

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Pests, what are they?

• Insects that have an end result of an undesirable
  or unacceptable affect on plants and trees and/or
  interferes with management objectives
• Cause damage and decrease aesthetics
• Stunt growth
• Vector diseases
• Tree mortality
• Directly or indirectly

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Why Pest Outbreaks Occur

• Stress caused to plant
• Water availability Light requirement
• Temperature/climate Nutrient balance
• Continuous food source
• Tree in non-native area
• Stress of transplant
• New enemies
• Invasive insect species

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Why Pest Outbreaks Occur

• Higher tree densities increases risk of insect
  infestation and disease
• Construction Damage
• Wounds inflicted upon bole of tree
• Soil compaction

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How do they effect the forest?

• Remember they can be beneficial such as
  pollination, prey upon other insects, and
  encourage natural selection (reduce the
  weak).

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Signs vs. Symptoms

• Symptoms are visual response of the plant due to
  an attack of an organism or abiotic factor.
• Leaf spots Wilting Discoloration
• Stunting Resin Multiple leaders

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Signs vs. Symptoms

• Signs are the visual presence of some structure
  formed by the attacker on the plant.
• Egg masses Insects Boring Holes
• Boring dust Spore Fruiting bodies

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Signs and Symptoms

• Examine entire plant
• Leaves/Needles Normal size, discoloration,
  deformed, holes, bumps, etc.
• Buds/Reproductive Buds abnormal growth, falling
  prematurely, rotting
• Branches and Trunk holes, cankers, conks,
  physical damage, oozing sap, etc.
• At the base of the tree Roots showing, burlap or
  container around roots, enough room for roots to
  grow, accumulating evidence boring dust, insect
  excretes, egg masses

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Definitions
Gall
Conk
Canker
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Categorizing Insects (Pests)

• By method of feeding
• Chewing Feed on plant tissue such as leaves,
  flowers, buds, and twigs
• Sucking Ingest plant juices by using a beak to
  break the surface of tissue
• Boring tunnel under the bark and feed on the
  trees phloem, heartwood or sapwood

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Western forest tent caterpillar
Feed on a variety of deciduous ornamentals,
aspens and willows
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Santa Fe Ski Basin

• Varity of Biotic Factors of Control
• Insect Parasites
• Predaceous beetles and bugs
• Moths
• Birds
• Nucleopolyhedrosis virus

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Extreme Populations

• Strip entire tree
• Travel down the tree and across ground in search
  of new foliage
• Can make roads slippery

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• Fall webworm

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Pear Slugs

• Introduced Sawfly
• Feed on cherry, plum, and other stone fruit trees
• Two generations year
• Leaves turn brown
• Usually little impact
• Wash off with insecticidal soap

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Elm leaf beetle

• Introduced species
• Likely cause of elm defoliation

• Two-tree generations a year
• Overwinter in homes
• Banding

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Boxelder bug

• Vacuum and house hold cleaners

• Prefer boxelder seed pods
• Overwinters in homes
• Insecticidal soap
• Two generations a year

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Aphids

• High number in short period of time
• Great deal of destruction to vegetation
• Serious pests as well as vectors of several plant
  diseases

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• Piercing sucking mouthparts
• Produce sticky honeydew excrete
• Feed on pinion in late winter and ponderosa in
  spring to avoid enemies

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Ladybird Beetle ?
Honeydew excretes ? on branches
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Tiger moth

• Usually not a serious pest in forest conditions
• Adults emerge in late July-August

• One generation/year
• Noticeable in late winter/early spring

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Tiger Moth

• Adults are colorful with irritating hairs
• Feed during fall and winter during warm days
• Retreat to tent for warmth
• Webbing found at base of tree

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Douglas-fir tussock moth
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• Females Flightless
• Movement by caterpillar

• Young Larvae are blackish with long hairs
• Later instars are very colorful
• Hairs cab be irritating

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• Many natural enemies
• Most controlling the nuclear polyhedrosis virus

• Egg mass formed on female cocoon
• About 300 white spherical eggs
• One generation year

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Pine tip moth
Nantucket
Southwestern
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• Attacks terminal buds
• Eggs laid on new shoots or terminal buds from
  March-June
• Larvae feed short time on needle base
• Bore into buds, laterals, and terminals and mines
  out the pith
• Growth is hindered but seldom kills the tree

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Pitch moth and bark moths
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Conifer sawflies

• Spring Feeders

• Summer Feeders

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Conifer sawflies

• Females cut slits into needles to lay eggs
• Gregarious feeders
• Young larvae skeletonize needles
• Older larvae consume entire needle

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• Wash off with a hose
• Prune branches
• Pick of by hand

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Western Spruce Budworm

• Most widely distributed and destructive
  defoliator of conifers in Western N.A.
• Attack Douglas-fir (red fir), white fir, and
  spruce
• Top kill, tree growth loss, and mortality in
  seedlings and saplings

Pictures Provided by USDA Forest Service
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Western Spruce Budworm

• Feeding larvae from May through June
• Mine or tunnel year-old needles, closed buds,
  newly developing vegetation, and reproductive
  buds
• July moths emerge, reproduce and die
• Larvae hatch in 10 days, they dont feed a
  second time but seek shelter for the winter

Pictures Provided by USDA Forest Service
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Western Spruce Budworm

• Management
• Thin to a single story canopy (i.e. thin
  over-story and then thin from below)
• Increase non-host species such as ponderosa pine
• Natural enemies
• Insect parasites
• Small mammals
• Birds

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Cooley spruce gall adelgid
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Overwinters as an immature female under bark
scales near the terminal spruce twigs
Early spring Female develops into stem-mother.
Deposits up to 350 eggs under her cottony mass.
Eventually, a winged generation is produced and
flies to spruce.
1-2 weeks later Eggs hatch and nymphs settle and
feed at base of young needles.
Winged adults fly to DF.
When nymphs nature, gall opens and nymphs crawl
to needles and mature.
Cone-like galls form around the nymphs.
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? Egg mass
Gall ?
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Needle miners
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Pinion Needle Miners
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Spider mites
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Piñon Needle Scale

• Bean-shaped bumps
• Attack one year old needle
• Suck sap from needles

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Piñon Needle Scale

• Males emerge in fall and overwinter at base of
  tree
• Female overwinters on the needle and emerges in
  spring
• Eggs laid in Feb-March

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• Eggs are yellow
• Held together loosely by a white cottony webbing

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Piñon Needle Scale

• Eggs can be rinsed off with a hose
• Must be meticulous about cleaning up debris after
  rinsing
• Pesticides are available

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Outline

• Common bark beetles
• Bark beetles attacking ponderosa pine in the
  Southwest
• Other bark beetle species on conifers
• Effects of bark beetles on forest conditions
• Management of pine bark beetles

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Common Southwestern Conifer Bark Beetle
Generain Scolytidae

• Dendroctonus spp. pine, spruce, Douglas-fir (6
  8 common species)
• Ips spp. pines and spruce (10 species)
• Scolytus spp. true fir, young Doug-fir
• Dryocoetes spp. true firs (subalpine
  corkbark fir)
• Phloeosinus spp. Juniper and cypress
• Pityophthorus spp. -Twig beetles mainly pines
  and Douglas-fir ( Over 30 species in NM plus
  other twig beetle genera including Pityogenes,
  Pityotrichus)

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Bark Beetles

• Bark beetles belong to Order Coleoptera and
  Family Scolytidae (6,000 worldwide)
• Every conifer in Southwest has associated bark
  beetles (often gt 1 species per host)
• Beetles are small in size (lt ¼ inch)
• Host, size shape, and egg galleries aid in
  identification of bark beetle species
• All life stages found in cambium or bark
• Most bark beetles introduce stain fungi

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Adult
Pupa
Larva
1/4
1/2
0
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Symptoms of bark beetles attack

• Crown fading
• Pitch tubes/streaming
• Boring dust
• Woodpecker activity

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Pine Bark Beetles in Southwest

• Pine engraver beetles (Ips)
• Several species
• Western pine beetle
• Roundheaded pine beetle
• Mountain pine beetle
• Southern and Mexican pine beetle (Chiricahua
  Mts.)
• Larger Mexican pine beetle
• Red turpentine beetle

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Ips Engraver Beetles
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Pinyon ips (Ips confuses)
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Piñon Outbreak in 2002
Piñon Mortality
East of Flagstaff, AZ
West of Cochiti Lake, NM
Near Mesa Verde, CO
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Western pine beetle (Dendroctonus brevicomis)

• Attacks 6-20 inch dbh pines in high density
  stands
• 2 generations per year (spring to October)
• Pitch tubes and maze-like galleries (frass packed)

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Stand structure bark beetles

• High density of trees
• Density of trees has increased more than 35
  times in the last 100 150 years
• High stand density leads to inter-tree
  competition for resources weakened defense
  mechanisms
• Density affects micro-site conditions and
  pheromone interactions that are favorable to
  beetles
• Size of trees
• Abundance of 80 yr. old, 6 14 inch dbh pine
• Mortality occurring across wide range of tree
  sizes
• Close association between stand conditions and
  Dendroctonus bark beetles, less clear for most Ips

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Response of bark beetles to changes in stand
structure
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Other bark beetles in the SWevery conifer has
its own beetles
Host Beetle
Spruce Spruce beetle
Subalpine/cork bark fir Western balsam bark beetle
White fir Fir engraver
Douglas-fir Douglas-fir beetle, Fir engraver
Junipers and Arizona cypress Cedar and cypress bark beetle (Phloeosinus spp.)
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Spruce beetle

• Causes large-scale mortality of Engelmann spruce
• Generation time ? 1 year
• Outbreaks start as result of disturbance

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Fir engraver (Scolytus ventralis) on white fir

• Incurved posterior
• Typically 1 generation/year
• Parent horizontal galleries
• Typically flies mid-summer
• Outbreaks start as result of disturbance drought

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Fir engraver (Scolytus monticolae) on Douglas-fir

• Incurved posterior
• Typically 1 generation/year
• Parent vertical galleries
• Typically flies mid-summer
• Outbreaks start as result of disturbance drought

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Douglas-fir beetle (Dendroctonus pseudotsugae)

• Very similar to spruce beetle is appearance and
  galleries
• Typically 1 generation/year
• Typically flies in May/June
• Pitch tubes uncommon
• Outbreaks start as result of disturbance

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Bark beetle ID review
Dendroctonus
Ips
Fir engraver
Western pine beetle
Scolytus
Dryocoetes
Western balsam bark beetle
Mountain pine beetle
Spruce beetle
Douglas-fir beetle
Red turpentine beetle
Pine engraver beetle (Ips)
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Impacts on Forest Conditions?

• Forest dynamics function species
  composition, tree size density, nutrient
  cycling
• Fire fuels dynamic process
• Wildlife winners losers, nut production
• Understory response predictable response
• Forest genetics potential bottlenecks
• Watershed hydrology short term increases in
  water run-off
• Recreation scenic beauty negative impacts

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Bark beetle control

• Prevention
• Silvicultural approaches are long-term
• Cultural practices are short-term prevention

• Suppression
• Attempt to reduce local populations of bark
  beetles
• Short term strategies

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Prevention

• Silvicultural strategies
• reduce tree density
• manipulating size
• change tree species composition
• Must manage thinning slash
• Avoid stacking green firewood or infested wood
  next to standing pine
• Watering spraying are okay, not fertilization

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Slash and bark beetles

• Slash removal is best
• Separate slash production in time space
• Dont pile slash in shaded areas
• Keep slash in a thin layer in full sunlight
• Chip haul
• Generating slash in August through December is
  safest time of year

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Preventative sprays

• Preventative sprays are available
• Sevin SL, Astro, Permethrin Plus C
• Spray must be applied up entire trunk to 4 inches
  in diameter
• Sprays work about one year

ag.arizona.edu/extension/fh/pdf_files/preventative
_spraying.pdf
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Suppression

• Treatment of infested trees
• No sprays available for treating infested trees
• Solarization infested logs covered w/ plastic
• Chipping, burning, peeling
• Removal from site disposal or sanitation

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Twig Beetles

• Normally attacks twigs and branches
• Can attack thin barked portion of trunk

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Woodborers ? bark beetle
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Woodborers
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Western cedar borer

• Hosts also included juniper and AZ cypress
• Can cause limb dieback or tree death
• Is a primary killer in large junipers

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True mistletoe
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Dwarf mistletoe
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Advanced condition that could take up to 50 years.
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Broom Rust

• Primarily a forest problem
• Infests spruces and firs
• Requires alternate host
• Kinnikinnick (spruce)
• Chickweed (fir)
• Prune infested branches
• Can kill tree if infests the bole
• No chemical control

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White Pine Blister Rust

• Introduced Disease in early 1900s
• Discovered in New Mexico in 1990.

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White Pine Blister Rust
Basidiospores infect needles in cool-wet weather
(July-Sept.) and overwinter
June-August rust is formed on leaves
One-several years sperm-ogonia appear on branches
April-May aeciospore are released and find second
host of ribies.
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Can you guess what it is?

• Juniper
• No fading
• No actual insects present
• Holes in the trees
• Some pitch tubes

Sap Sucker
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Management of Pests

• Determine what is attacking plants
• What is present in area
• What is most damaging in area
• What is most damaging to that species of tree
• Once identified control can begin
• Damage potential
• Life cycle
• Control options

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Pesticides, what to consider?

• If at all possible use non-chemical methods
• Natural predators, parasites, and pathogens
• Remove by hand
• Prune
• Remove breeding grounds
• Consider tree resistance and tolerance
• Environmental influences
• Unfortunately this not always work quickly enough
  to keep from getting undesirable injury or damage

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Pesticides, what to consider?

• Is it feasible?
• How large of scale? Economically?
• Generalists vs. Specialists
• Generalist kill a wide variety of insects
• Specialist limit to a few families or order
• Pest resistance
• Non-target insects and trees (drift)
• Kill natural enemies of the current or other
  pests
• Kill other trees or plants near by

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Drift kill from highway weed control
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Pesticides, what to consider?

• When you use a pesticides always be sure to
  follow the label carefully
• Make sure you use the appropriate chemical in the
  right concentration/dosage specified for that
  insect and tree
• Use chemical a the correct time of life cycle of
  the insect
• For larger or more difficult applications hire a
  professional

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Prevention

• Inspections
• Examine plants when possible for signs and
  symptoms
• Familiarize yourself what insects are common in
  that area
• Proper plant selection
• Select plants adapted to growing conditions
• Dont plant trees that are currently being
  infested
• Dont plant certain species together

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Prevention

• Maintenance of Area
• Prune broken, damaged, or dead limbs
• Avoid damage with lawn equipment, such as, mowers
  and weed-eaters
• Mulching to reduce grasses from around base of
  tree
• Reduces competition
• Removes ladder
• Remove sites that can harbor insects
• Piles of leaves or grass clippings

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Questions?

• Images and photos provided by
• USDA Forest Service
• NMSU Coop. Ext. Service
• University of Minnesota
• Colorado State University, CES
• Ohio State University