Sapsucking Insects
OBJECTIVES OF SAPSUCKING INSECTS
At the end of this section students should be able to:
1) Describe the symptoms and damage of sapsucking pests.
2) List the major types of sucking pests and give example of one of
each type that is important in commercial or urban forests.
3) Explain why control of these pests is so difficult.
4) Describe the relationship between some sapsucking pests and
forest pathogens.
5) Describe control approaches used in management programs for
these pests.
Sapsucking Pests
Sapsucking pests are Homoperta & Hemiptera
Sapsucking pests are also Arachnida (mites)
Sapsucking pests have piercing-sucking mouthparts
Sapsucking pests are difficult problems
Because they are:
1) Inconspicuous
2) Hard to control
Sapsucking pests rarely kill trees
Scale insects, some adelgids are the exceptions
Population Dynamics – P/S Insects
Insect populations are affected by:
1. Destruction of natural enemies
2. Dust accumulation
3. Very cold weather
4. Dispersal (wind, people, quarantines)
5. Plant Resistance
1.Numbers increase dramatically when insecticides are
used as often they kill beneficial insects more
effectively than the pest.
2. Numbers increase when dust accumulates on plants
as dust interferes with natural enemies searching
ability
3. Plant Resistance reduces population numbers.
Sometimes only reasonable approach to controlling
sapsucking pests
4. Numbers decrease in very cold weather as this kills
individuals and reduces quantity quality of food supply
5. Natural dispersal by wind, crawling, flight. Most
major pests introduced on infested nursery stock so
quarantines significantly reduce spread
Symptoms and Damage
1) Damage from removal of nutrients and toxic saliva
Discolored and/or curled foliage
1) Damage from removal of nutrients and toxic saliva
Abnormal shoot growth
1. Damage from removal of nutrients and toxic saliva
Premature leaf drop
1) Damage from removal of nutrients and toxic saliva
Branch and/or tree mortality
1) Damage from removal of nutrients and toxic saliva
Adelgid Caused Mortality on Fir
2. Damage from excretions
Honeydew
and/or
black mold
on
foliage
3. Damage from oviposition activities
Cicadas, tree hoppers, sawflies Tree crickets
Cicada oviposition damage
4. Disease Transmission
Aphids and Leafhoppers
4. Disease Transmission
Elm Phloem Necrosis my kill
more elms than Dutch Elm
Disease
Cause: A Phytoplasma
Vector: Leafhoppers
Characteristic “butterscotch”
Discoloration of inner bark
Common & Important / Unimportant
Sapsucking pests
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Asian Hackberry Woolly Aphid
Gall Forming Insects
Hemlock Woolly Adelgid
Spruce Adelgid
Beech Bark Scale
Saratoga spittlebug
Hemiptera
Aphids - Many species and types
Alate (winged) aphid
Apterous (non-winged)
aphids
Cornicles
Asian Woolly Hackberry Aphid
Pine Aphids
(Cinera spp)
White pine aphids
Spruce Aphids
Spruce aphid damage
Gall Forming Insects
• Tend to be host specific
• Interesting life cycles
• Leaves, twigs, stems, petioles
• Unsightly
• Urban vs Forest settings
Hackberry gall psyllid
Aphid Galls on Hickory
Vagabond gall aphid
Poplar Petiole gall aphid
Oak Sower Gall (a Wasp Gall)
Spruce Gall
Adelgid
Hemiptera: Adelgids - many species
Once called aphids
Differ in insect:
Morphology - no cornicles
Life Cycle - always lay eggs
Hosts - only conifers
Adelgids
Hemlock
Wooly Adelgid
Accidentally
introduced to PNW 1920’s
Found in Virginia in
1953
Adelgid Bole
infestation
Hemlock Woolly Adelgid
Feeding causes needle
drop.
Complete defoliation &
death of tree.
Can kill a tree in a single
year
Introduced Predator of Hemlock Woolly Adelgid
Video – Hemlock at Risk
Management - Hemlock Woolly Adelgid
Private vs Public Lands
Balsam Woolly Adelgid
•Another conifer pest killing trees
•Imported pest from Europe
•Weakens and/or kills true firs
•1 of most important sucking pests
•2- 4 generations / year
•No Males Known to exist
•Few economical controls
Balsam Woolly
adelgids – Feeding
on tree trunk
Feeding Damage
Bole infestations cause formation
of reddish colored compression wood
Poor H2O conduction qualities
Toxic saliva causes increase in
cell number
cell size
thickened cell walls and tracheids
Butterscotch
wood of a
balsam woolly
adelgid infested
tree
Feeding Damage
Heavy crown infestations cause formation of twig
gouting and reduces new shoot growth and
eventual death of the tree
Impact on true firs in North America is severe
•Complete stand mortality
•Significant timber losses
•Reduced tree growth
•Reduced seed production
•Killed millions of board feet
Management & Control in US
Few controls available
Pine bark adelgids – native insect
Found throughout North America
Attack Scots, jack, pitch, white and
Ponderosa pines
Stunt growth, produce honey dew, &
occasionally kill trees
Spread is slow due to reduced mobility
Pine bark adelgid
Hemiptera - Scale Insects
Soft Scales – cottony, waxy
Armored Scales – hard covers
Eriococcid Scales
Margaroid Scales
Cottony Maple Leaf Scale
Cottony Cushion Scale
Tortoise Scale and Sooty Mold
Pine Tortoise Scale and Sooty Mold
Striped pine scale and sooty mold
Hemiptera
The Armored Scales: covered with a
hard wax or protective coating
Hemiptera Oystershell scale
Hemiptera
White Pine Needle Scale
Hemiptera
Beech Scale
Beech
Bark
Disease
Expansion
Black area
Current
Distribution
Of beech
Disease
Grey area
Distribution
Of Beech
Trees
Beech Bark Disease Cycle – Insect & Fungus
Beech Bark Scale
Beech Bark Scale – Close up
Fruiting bodies of fungus – infecting scale wounds
Cankers coalescing – fungus/insect
Yellowing & Declining American Beech
Management & Outlook
Beech Bark Scale
Eriococcid Scales
European Elm Scale
Hemiptera
Red Pine Scale
Red Pine Needle Scale Adult Male
Red pine scale –
Matsucoccus resinosae
•Introduced pest
•Large numbers of Red pine killed
•Infested trees die within 5 years
•No effective controls (except cold (-23 C)
•Currently large tracts in Connecticut being
harvested due to mortality
Hemiptera
Margaroid Scales
Pit Scales - they cause small pits
Asterolecanium spp - Pests of Oaks
Heavy infestations kill trees, especially
when associated with drought or
Anthracnose fungi
Pit Scales
Hemiptera
Plant Bugs - Miridae
Hemiptera
Boxelder Bug
Hemiptera
Lace bugs
Spider Mite
Damage
Spider Mite
Damage
Management Approaches
Do Nothing
Insecticides
Natural Enemies
White Pine Needle Scale & Lady Bird Beetle Predator
Management Approaches
Cultural Management Strategies
Keep trees healthy
Regulations – Quarantines
Integrated Pest Management
Example: Rating system for Saratoga
Spittle bug on Red Pine
Saratoga spittle bug
Immature insects feed on alternate
host which includes sweet fern
Adults feed on pine (no spittle)
Serious pine pest – lots of mortality
dieback, growth loss
Saratoga Spittlebug
Damage on Red Pine
Hemiptera
Spittle bugs
Pine spittle bug – serious pine pest in forest, urban
and Christmas tree plantations
Spittlebug adult
Saratoga spittlebug on Alternate Host
Sweet Fern - Alternate Host of Saratoga Spittlebug
also feeds on willow shoots
Saratoga Spittlebug Decision Model