Conifer Defoliators

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Conifer Defoliators
Lepidoptera Budworms Eastern Spruce
Budworm Western Spruce Budworm Jack Pine
Budworm Tussock Moths Douglas Fir Tussock
Moth Pine Tussock Moth Casebearers, Bagworms,
Webworms Hymenoptera Conifer sawflies
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Eastern Spruce Budworm
Natural Resources Canada, CFS., Laurentian For.
Cent., Pierre Therrien
Native Insect Eastern Canada, New England,
Upper Midwest Balsam Fir, White Spruce, Other
Spruces Large - Scale, Cyclic Outbreaks
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Natural Resources Canada, Can. For. Serv.,
Laurentian For. Cent., René Pâquet
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Eastern Spruce Budworm
Natural Resources Canada, Can. For. Serv.,
Laurentian For. Cent., Jacques Morissette
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Aug Eggs hatch Early larvae overwinter
July-Aug
Pupate in July
Larvae feed May-July
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Natural Enemies of Eastern Spruce Budworm
Predators Birds Parasitoids Eggs Trichogramma
minutum (Chalcidae) Early larvae Apanteles
fumiferanae (Braconidae) Late larvae Actia
interrupta (Tachinidae) Meteorus
thrichynotus (Braconidae) Pupae Itoplectus
conquistidor (Ichneumonidae) Pathogens NPHV Nos
ema (Protozoa) Fungi
Relationship to Population Cycles
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Impacts
Tree-Level 1 yr 30-90 radial growth loss
Flower cone mortality 2 - 3 yr Root
mortality Top death Mortality to
bark beetles 4 yr Tree death
Stand-Level Conversion to early succession
plants Fire Nutrient cycling Altered wildlife
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Population Cycles
Major outbreaks _at_ 25 yrs. Intensified by Forest
Management Practices Key Factors Dispersal and
Establishment of early instar larvae Stand
Structure Phenological Coincidence with Opening
Buds Host Relationships Overall Nutrients more
important than Toxins Protein more important
than Carbohydrates Early instars in Late season
Foliage - low in N Third instars in Early
season Buds - high N and protein, but they
must be open (e.g., Black spruce asynchron) Late
instars in Mid season Foliage- low N, high
Carbohydrates
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Sampling
Aerial Photos Landscape Pheromones Egg
Mass and Larval Surveys Tree
Good sampling protocols available at each level
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Jack Pine Budworm
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Jack Pine Budworm
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Jack Pine Budworm Host Specificity
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Recent Expansion of Jack Pine Budworm onto Red
Pine
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Conifer Defoliators
Lepidoptera Spruce Budworm Jack Pine
Budworm Douglas Fir Tussock Moth Pine Tussock
Moth Casebearers, Bagworms, Webworms Hymenoptera
Conifer sawflies
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Douglas Fir Tussock Moth
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Douglas Fir Tussock Moth (Lymantriidae)
Native Species Northwest from Cascades to
Continental Divide Eruptive Population
Dynamics Wingless Females
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Life Cycle of Douglas Fir Tussock Moth
Univoltine Overwinter as Eggs (250 eggs in
single mass) Larvae emerge in spring Disperse
aerially Early instars feed on undersides of new
foliage, in upper third of crown Pupate on small
branches Wingless females, Winged males mating
oviposition on foliage
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Host Range of Douglas Fir Tussock Moth Douglas
Fir True Firs
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Impact of Douglas Fir Tussock Moth Tree Level 50
- 75 Growth Reduction Susceptibility to Bark
Beetles Stand Level Released understory growth
Conversion to pine Increased nutrient cycling
from frass clipped needles 10X available N
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Population Dynamics of Douglas Fir Tussock Moth
Intrinsic Cycles - Every 8 - 9 yrs. Delayed
density dependence between herbivore / natural
enemies Control by generalists and parasites
-gtRelease -gt Virus Site Weather Factors Edge
of natural range of host (DF / Fir - Pine
Grass) Warm, dry conditions Shallow Soils
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Population Dynamics of Douglas Fir Tussock Moth
Forestry Practices Conversion from pine to DF or
Fir Fire suppression Grazing
Mason Wickman 1988
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Douglas Fir Tussock Moth Natural Enemies
Generalists Birds Nuthatch, Junco
Chickadees Ants Specialists Parasitoids
NPV
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Management of Douglas Fir Tussock Moth
Silviculture Preventative Site selection based
on risk rating Susceptible Sites Low
elevations East slopes Ridge tops High tree
density Large crowns High DF, Fir
Preventative Management Favor soil moisture
and nutrient cycling processes Avoid
compaction Thinning Retain slash
Warm, dry
Larval dispersal
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Management of Douglas Fir Tussock Moth
Silviculture Corrective Sanitation
harvest Favor natural regeneration Sampling Aer
ial photography satellites Pheromones Egg
mass and larval sampling Insecticides Bt
Consider Timing, Role of host trees NPV Pheromone
s
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Conifer Defoliators
Lepidoptera Spruce Budworm Jack Pine
Budworm Douglas Fir Tussock Moth Pine Tussock
Moth Casebearers, Bagworms, Webworms Hymenoptera
Conifer sawflies
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Pine Tussock Moth (Lymantriidae)
Native Species Jack Pine (Rarely others) Mostly
in WI, MN
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Larvae feed on current foliage in spring
Larvae emerge in late summer. Feed on
eggs. Overwinter as L2-3
Adults in mid summer
Oviposit on foliage
Pupate on foliage
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Pine Tussock Moth Natural Enemies
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Budworms vs. Tussock Moths
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Conifer Defoliators
Lepidoptera Spruce Budworm Jack Pine
Budworm Douglas Fir Tussock Moth Pine Tussock
Moth Casebearers, Bagworms, Webworms Hymenoptera
Conifer sawflies
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Larch Casebearer
Introduced Feeds only on larch Throughout range
of larch Originally caused large-scale
outbreaks Now largely controlled by Introduced
parasitic wasp Occassional outbreaks
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Larch Casebearer
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Larch Casebearer Feeding
Univoltine Overwinter as pupa Feed in summer
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Bagworms Biology, Impact, Control
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Pine False Webworm
UGA1247144
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Conifer Defoliators
Lepidoptera Spruce Budworm Jack Pine
Budworm Douglas Fir Tussock Moth Pine Tussock
Moth Casebearers, Bagworms, Webworms Hymenoptera
Conifer sawflies
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Sawfly Life Cycle Mating Oviposition
Facultative parthenogenisis Sexual dimorphism
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Oviposit in Needle Use ovipositor to slit resin
flow
Multiple eggs per needle
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Sawfly Egg
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Early Instar Sawfly Larvae
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Sawfly Larvae
Larval Prolegs (prs) Sawfly 6 Lepidoptera
5 or less (3-6, 10)
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Sawfly Larvae Feeding on Prior Years Foliage
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Sawfly Cocoon in Soil Prepupae
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Sawfly Larval Defensive Regurgitation Against
Predators
Resin pouches
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Natural Enemies of Conifer Sawflies Parasitoids Ch
ickadees Some generalist arthropods
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Sawfly Eggs Killed by Pine Needle Dessication
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Redheaded Pine Sawfly
Broad host range Feeds on both previous and
current years foliage Intermittent outbreaks in
young plantations Populations build along
hardwood edge
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European Pine Sawfly Scots, Austrian 1 generation
/ yr. Introduced Pine Sawfly White pine (Jack,
Scots, Red) Christmas Trees Early larvae
Gregarious Late larvae Solitary Pupate on
tree 2 generations / yr. European Spruce
Sawfly White spruce
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Larch Sawfly
Larch only Population almost entirely female 1
generation / yr.
Female oviposits under bark of current twigs
Oviposition causes shepherds crooking Larvae
feed gregariously on foliage on previous years
twigs
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Regionally Important Conifer Defoliators
Lepidoptera Needle Miners Lodgepole needle
miner Silkworm Moths Pandora Moth on ponderosa
and lodgepole pine Inchworms (Geometridae)
Western Hemlock Looper Coastal range Eastern
Hemlock Looper Newfoundland Sulfur Butterflies
Pine Butterfly on ponderosa pine Coleoptera Scara
baeidae Pine chafer